Mutter merged an implementation of this protocol a few weeks ago: gitlab.gnome.org/GNOME/mutter/-/merge_requests/5071.

The author also made a fun demo of this: https://files.catbox.moe/q3ut43.mp4 (comment link).

Uhh depends on your rig I guess. I build the various emulators from git and some of them like vita3k can take awhile.

But for me its more about being able to leave the update unattended, knowing that when I come back they will all be done and I can close the terminal window.