Steam deck already supports this

Yes, but this legislation seems to be aimed at making them replaceable without having to take the device apart at all.

I mean, what is the difference behind removing the entire back with a few screws and removing a battery cover with a few screws? The Deck battery is user-replaceable. That said, I wouldn’t mind a battery compartment and for the battery not to be held down with adhesive (not sure if the Deck battery is or not, but lots of devices using flat cell batteries do).

The battery is strongly adhered to the Steam Deck. The adhesive loosens with constant, steady force, and it will require repeated heating and prying cycles.

It’s pretty much the Achilles’ heel of the Steamdeck’s repairability.