The continent had been inhabited by humans for tens of thousands of years by 1849, which, I'd assume, means tons of different societies used that land over the years.
It seems like one group or another would have found it was worth collecting for some reason. It's bright, pure, yellow, and insanely heavy. It seems like one of those properties would have been useful. Even if they didn't use it as a store of value or an object of religious significance, its density would make it a useful ballistic projectile, or a doorstop, or cookware, or something.
There were Central and South American peoples who used pretty expert looking craftsmanship to make things from gold that had some clear significance. From what I understand there were trading networks where, even if you never came in contact with the people who eventually wound up owning the goods you traded, you still would have known that someone somewhere was looking for it because a trader would tell you.
But then there's stories of '49ers scooping up fist sized lumps just sitting in a stream. Did the trade networks just not extend far enough South? Do we have written records or oral histories about how any groups viewed it, if they cared at all?
The gold was, simply, not that apparent or plentiful. Because it was (and is) extremely valuable, the retrieval of just a small amount of gold can represent a good day's wage.
Gold has limits when it comes to practical use, particularly for cultures that do not engage in metal smithing. The imagined uses you suggest could all be handled better with other more readily available materials.
Setting aside the issue of indigenous people, keep in mind that Spanish speaking people were extending the Spanish-Mexican/international trading network into Northern California long before gold was discovered there - and yet they did not notice it.
Most of the gold was in the bottom of stream beds or underground/mixed in soil. Most was not glittering at the surface waiting to be picked up. And most was in the form of small flakes that had to be separated from worthless dirt and then picked out with tweezers or - more commonly - mixed with mercury to form an amalgam that had to be treated to separate it from the mercury. Placer mining, as conducted by the 49ers was a lot of work, and it wasn't uncommon to declare a day where they made $3 or $4 dollars extremely good: this is when gold was selling for $16 an ounce, meaning that spending a day retrieving less than 1/4 of an ounce of a very heavy substance (meaning, the size of the amount was small) made for a good day.
There were widely circulated anecdotes of 49ers striking it rick with a large nugget "scooped up from a river bed," but this was akin to the stories of people who made it rich with a .com business - it happened, but it was rare. That said, the stories were popular, so they circulated widely.
For the most part, people worked very hard for not much gold. Some made "their pile" - accumulating several thousand dollars to return to "the states" to buy a farm - but this was not a majority of the 49ers: the gold was just that scarce and hard to retrieve even while it was sufficiently plentiful to inspiring dreams.