I think most of it can be seen as a proof on concept. A statement by zsKnight is read in the YT video where he says that he wants to work on Super ZSNES full time via funding through Patreon.

Given the nature as a proprietary application written using Unity, I wouldn’t be surprised if Super ZSNES will be sold on Steam in the future, similar to 3dSen. It’s not like a Unity app can ever be fully FOSS because Unity itself is not FOSS.