Kate, we are 2.75 years old and very early on, before Springboard or commercial licensing as we now know it existed, we promoted and allowed guests to use their own accounts.
Turned out to be way more trouble than it was worth. In the year we offered that as an option, 8 folks did use their account. Issues were that games had to be loaded (hours of downloading time), so it’s not like they could play the day they showed up. Had to come back the next day. Then it also cluttered the Steam account with games other people could see, but not play.
We did it primarily so folks could play more games, but now that there are 300+ to choose from in SB commercial marketplace... and we have around 200 for them to play - that option is no longer offered.