Probably nothing. This is more steamdeck related stuff since the SteamOS is based on ArchLinux. And even then, it does not mean much for SteamDeck users. They wont notice much at all really. This might help with development a bit on valves end. The big news is really for ArchLinux users and maintainers which will see more effort in the development of that distro.
There is some wild speculation that maybe this makes arm for Arch Linux more official in the future. Which is based of the other recent news that Valve are creating an ARM emulation layer for running games on ARM devices. Which means maybe they are working on an ARM device and maybe need to start working on getting ARM support for Arch. Though again this is all wild speculation.
And then relabel all the old standards when they create a new one so every generation you need to figure-out what al the new names mean.