If the tradeoff was being able to destroy most of the USA's pacific fleet, leading them to enter the war earlier, (or possibly at all) were the attacks worth it? If they hadn't attacked, I assume we would have eventually gone to war against Germany, but would we have fought Japan?
There's an entire AskHistorians FAQ section about this, at https://www.reddit.com/r/AskHistorians/wiki/faq/militaryhistory/wwii/fronts#wiki_pearl_harbor Mentioning previous answers is not intended to discourage further discussion. Follow-on questions, information, and debate are welcome.
I think the most applicable in terms of strategy is "Why did Japan attack Pearl Harbor?", with the answer by /u/kasirzin at https://www.reddit.com/r/AskHistorians/comments/2r7i4c/why_did_japan_attack_pearl_harbor/cndiyuu/ .
Other posts talk about details, tactics, and follow-on strategy.
"Was the attack on Pearl Harbour a gamble by the Japanese Empire, or did they truly believed such a attack would cripple the US to the point of not winning the war?", answers by [deleted] and /u/ParkSungJun and /u/Tricericon under https://www.reddit.com/r/AskHistorians/comments/22oyi9/was_the_attack_on_pearl_harbour_a_gamble_by_the/ . Lots of valuable discussion.
"What was Japan's (long-term) plan when they attacked Pearl Harbor?", answer by [deleted]s, under https://www.reddit.com/r/AskHistorians/comments/23mjp3/what_was_japans_longterm_plan_when_they_attacked/
"What did the Japanese expect the reaction to Pearl Harbor to be?", answers by paburon and vontysk under https://www.reddit.com/r/AskHistorians/comments/1pvif4/what_did_the_japanese_expect_the_reaction_to/ .
"Why didn't Japan invade Pearl Harbor and finish it off afterward?", answers by vonadler et al. under https://www.reddit.com/r/AskHistorians/comments/2hf1a7/why_didnt_japan_invade_pearl_harbor_and_finish_it/
So those answers that you've had linked are all pretty much good and factual and worth reading, but they sort of dance around the issue.
If we accept that was has been decided upon and the Southern Strategy has been decided upon as the opening move by the Japanese military we can also at least acknowledge their assumption. The IJN leadership both aboard the Nagato with the Combined Fleet and at HQ with the Naval Ministry was that the US would not stand by if they essentially tried to bypass the Philippines to strike at other colonial possessions. To say nothing of the unease of allowing such a huge threat to their sealanes back to the Home Islands posed by US aircraft and naval assets based out of the Philippines which could also serve as safe harbor for other Allied units.
So now to secure the other more valuable places we need to secure the Philippines and that means war with the US. And war with the US, as lead by Yamamoto as the paragon of aggressive elan in the IJN meant, as laid out in the links, the attack on Pearl as part of the plan.
So now to your actual question it basically comes down to 3 competing issues to weigh, the material impact, the organizational impact, and the morale impact.
Materially it was immediately traumatizing but nothing that was in Hawaii that day was going to be Sine Qua Non to the US defeating Japan. At least nothing that the IJN had the ability to really damage, even if we grant them the near impossible to launch 3rd wave, the damage able to be inflicted on say the fuel farm is usually overstated along with say Drydock #1.
So that shifts us to the Morale, as obviously the attacks heavily galvanized the home front even if it crashed locally for the military in Hawaii and the Pacific. But other factors like 50 years or racial tensions and a huge helping of propaganda along those lines certainly could have added that particularly vicious and uncompromising aspect of the war in time without the attacks too. But it is fair to at least say that the attacks always provided an easy deflection when voices spoke up about the possibility of a negotiated peace.
So that leaves us with the Organizational impact, and one that I think is often ignored or under appreciated. Frankly for almost 2.5 months the Pacific Fleet was incapable of anything approaching the level of planning and operational competence that it would need as 1942 wound on. And in part this was because of the terrible fog that settled over CINCPAC HQ and most ships of the fleet creating a negative feedback loop of sorts. This is perfectly typified by the aborted Wake Relief attempt. Kimmel actually sets it in motion to provide more equipment and men to the garrison while getting the Pan Am civilians out, and cover it with one carrier, with another on distant cover, and the other striking the Mandate Islands to provide distraction.
But a comedy of errors unhelped by the shocked state of the staff, including nobody telling the skipper of the ship they were using that he should expect troops and supplies to start being loaded on, meant it was never to be. Ships sailed late, supplies were sloppily loaded, refueling was hurt by bad weather, and the position and mission of the carriers changed several times while they were already at sea. In the end Wake fell with the forces still hours away from even launching aircraft at max range to aid.
This is just one example of the near panic and paralysis that PACFLT found itself in, it remained when Pye became the interim leader, and took a good while for Nimitz to work out. Indeed even the Mandate Raid of February were a sloppy plan pushed forward in part just to do something (and based on parts of War Plan Orange) to start getting the force into shape. While direct fear of another attack on Pearl or threat to the area meant that a carrier force was nearly always kept patrolling Hawaii as opposed to being used elsewhere, which for its trouble the Saratoga caught a torpedo and was out of the war for the crucial period including Cora Sea and Midway.
So we can certainly that removing even the shadow of a credible threat from the USN for almost 3 months and a tentative one for several more certainly was a real benefit to come from the attack. Even if the still outnumbered USN forces couldn't have truly threatened the drive into the DEI there was still little interference in the fortification of the Eastern edge of the empire in places like Rabaul, and the Marshalls and Gilberts. So it in effect simply allowed the IJN to go through with their plans for the opening stage of the war on seizing the Southern Resource Area and fortifying their sea frontier by landing forces on additional mutually supporting islands and bases.