@Dryish:
It basically gives Oda a chance to think of anything super convenient that helps the SHs out of trouble whenever he's feeling lazy and doesn't want to come up with a super convoluted plotline that would explain how and why they beat someone without retconning his powers or just got out of trouble easily.
We haven't seen anything of the sort just yet (the strange reedboat thingy is a borderline case), but the fact that he even created such an easy-way-out tool for himself is already worrisome and could very well be an indication of what is to come.
I think it's fine, as long as he's restricted to what we've seen from him. For example, he has already reused the trampoline plant, and it's not like his stars have disappeared completely. I also think that this has always been Usopp's place on the team: Generally bad at fighting, excellent for utility.
I like how Usopp was about to ask Rayleigh the nature of OP. That moment really struck me for some reason.