There are many types pf plywood. Utility grade, construction grade, lite ply, marine grade, aircraft grade. Different cores, different glues, different number of plies. Different applications. And, of course different prices.

Softer FW materials will compress and allow loosening of the attaching hardware, necessitating checking and re-tightening.

I use aircraft grade which is usually birch faced with no internal voids, and with strong waterproof glues. All securing is with long set epoxy and cross screws or dowels, coupled with triangular stock and doubling of the fuselage as required.

Of course, I think too much about it.

Works for my applications; good luck with yours.