I mean, see above for my estimate of how big that contribution is, discounting the effect of the rather unLinux-y experience of using the Deck.
Proton and Wine support help, although I genuinely would like to see more laptops shipping Linux by default more than I care about the Deck. I recently tried to move a laptop to Linux and the terrible support for custom hardware made it unfeasible. That machine is back on Windows now.
The underreported key to Linux on the Deck is that it's configured for the hardware out of the box. In a world where modular, standardized desktop computing is not mainstream outside techie circles, Linux's problem is that most normies on Windows aren't on a desktop PC with AMD gear, they're on some slightly but noticeably custom branded laptop still running its default Windows install.