This would presumably let x86 windows games run on ARM hardware.
This is almost certainly meant for the next Valve VR headset, but ARM has so much better power efficiency than x86 that a future ARM based Deck would be a huge improvement to battery life.
Also see this tweet:
VR games that have already secretly pushed Android ARM builds onto the Steam Store are ran via Waydroid (androidARM to LinuxARM)
VR games that do not have an ARM build on Steam (windows x86) are being translated/emulated via ProtonARM and FEX
AMD is on a much better process node than Intel, but their battery life still isn’t as good as Apple’s. Particularly under low to medium loads. My M1 MBP easily gets 12 hours of battery life under a real load. My AMD powered ThinkPad is closer to 7 hours, and my Intel machines get like 4, on a good day.