The crew

[Lewis63421]

Does the crew add anything other than extra benefits for choosing their weapon? Cause I will take Azurene as a crew member and nothing happens

[Döngs]

You unlock their unique captain upgrades. Everything you bought for them on the first tab of the Space Cube Upgrade screen. If you haven't maxed out their unique upgrades, the ones you are missing can appear on level-up.

[Smoel]

You need the weapon of the crew member(captain) you picked. So if you chose Azurene, you will also have to get plasma cannon as an upgrade.

[Angry By Default]

besides the weapon, when u get the meta upgrades for the captains u can get the hull/shield and w/e else they have when u crew recruit them without having their weapon, so just consider them as a better version of the basic upgrades

[The Almighty 404]

Each captain has 4 sets of upgrades. Two are for their ship's weapon, and are already unlocked by the time you unlock them as crewmember, so you need the weapon and the captain to access them. The other two are unlocked once you get further, and apply to other traits like boosters or shields.
When you upgrade the captain in the space cube menu, the upgrades you've bought apply whenever you add them to your crew, either if they are your starting captain or if you invite them later. So, if you have all their available upgrades maxed up and lack their weapon, you might not realize the changes, especially if you have only unlocked their super weapon upgrades.

[CascadeHush]

Yeah, kinda what he said. It could be explained clearer in the UI, but then the game is in early access. In practice, like everything else in this game, F around and find out. I do think it could be a bit more streamlined, unlocking the co-pilot without the weapon doesn't do anything unless you've unlocked their passives. It does actually tell you when they appear on the upgrade screen what you get by choosing them but you might be missing stuff if you don't have all the pieces in place.