While the support itself doesn’t necessarily mean OS-level toggle like the Steam Deck has right (which I believe is still at FSR 1), it still could be a nice touch for the titles that choose to implement FSR 4.
Maybe the community adds the OS-level support unofficially, somewhat similarly to Lossless Scaling right now (although perhaps for free). This is just my uneducated guesswork, please see this comment for proper expectations:
That’s partially true, unfortunately some games do not work with the FSR4 upgrade via OptiScaler, and on top of that there’s a plausible risk of getting banned in games with anticheat