Aluminum over plywood or right over studs?

[epic_username]

Hello all, I tried to search but couldnt find anything quite related...

I plan to skin my teardrop with some aluminum I stripped off a travel trailer with my dad. I also plan to have studded walls, so I can put some insulation in there, rather than just plywood. I noticed, in stripping that travel trailer, that the aluminum was stapled right to the wall studs. However in my tent trailer that I am stripping to build my teardrop on, there is a layer of 1/4" plywood between the studs and the aluminum.

So I was wondering, is one way better than the other as far as water sealing or general insulation? Or does it pretty much come down to preference?

If it matters, my main tow vehicle is rated for 7000, so weight isnt a huge concern.

Cheers, David