The reality of the situation is Usopp is that poor friend who had to be cut off because he couldn't keep up with the rich friend's lifestyle. Luffy is just nika these days anyway, but he definitely thinks very little of most of the SHs, he has no respect for them whatsoever cause they are less than fodder.
I think this is literally just true for Usopp. Nami even without Zeus provides a hax navigator you do actually need. But she has Zeus, and that alone puts her kinda up there power wise. Nothign crazy but she can certainly beat some YC3 type guys if she plays it smart / Oda ever wants to throw her a bone.
Robin can pull her weight against Black Maria, Franky can one shot Vice Admirals and build crazy tech, Brook during Wholecake more than paid for his admission even if he literally only plays music from this point forward. Hell, even Chopper HAS bitch slapped Queen and can provide a useful skill set to the crew.
But Usopp? His stans will hate you for saying it but he literally IS worse than fodder these days. You cant tell me if Luffy just recruited some random giant with a bow that would not be a flat improvement over Usopp. As long as the giant is kinda the size of Lokis mom they would not even be forced to adjust the Sunny to fit them on-board.
Usopp was kinda cooked the second Franky got on-board lowkey. He was sorta the "crafty / inventor" guy besides his snipping gimmick, but now that Franky is part of the crew? Usopp has his goddamn beans and thats kinda it.
He will probably make some speech to help the giants out, and might luck his way into beating Van Augur, but that man is NOT somebody who anybody can make a case for being a true New World pirate. That random filler Beats Pirate who boxed with Luffy for five seconds would beat Usopp low diff.