A lot of older PC games can run just fine on modern phone hardware. I'd buy a SteamOS version of a phone that has some modular or built-in set of buttons and analog sticks. I don't know how the app ecosystem would work for sensitive things like banking but it's mostly a minor issue for me.
depends.
if it's basically a continuation of the xperia play, but otherwise a regular modern day smartphone with passing safety net, unlockable bootloader, a 3,5mm jack, sd card slot, stereo front firing speaker, decent camera,
absolutely.