If you're a fan of cloud gaming, you may want to take a little look into Netris. The developers say it's a GeForce NOW alternative, one you can self-host with it being open source. They're also keen to highlight some Stadia-like elements of it too.
TL;DR: Simultaneous library sharing. Before, only one user could use a library at a time. Now, up to 6 users can simultaneously play any game from the same library.
This is what Netris is touting users to exploit when they say:
Steam Library Sharing
Grant access to your Steam library, so everyone on your team can join in on the fun without additional purchases.
https://store.steampowered.com/news/app/593110/view/4149575031735702628
TL;DR: Simultaneous library sharing. Before, only one user could use a library at a time. Now, up to 6 users can simultaneously play any game from the same library.
This is what Netris is touting users to exploit when they say:
A “Team”, lol wut?
Neat, now my family can play non-split screen games