Why was Portugal invited to join NATO at its onset? It was arguably the poorest country in Western Europe and was ruled by a dictator. What were they bringing to the table that other nations would have been benefitted from?

I am really no expert on this, but I think it boils down to the Azores. Being in the middle of the Atlantic, it has a lot of strategic military appeal.

The US especially could use a base in the Azores to get a decent foothold near Europe, but for that Portugal needed to join NATO.

Take this with a massive grain of salt, please