And to play two copies of the same game at the same time, any 2 members of the family could own it. So my brother and I can each buy a game, and then my mom and sister could play it while we are at work. My sister can't work, so she has a lot of time to fill but can't afford to buy games. We do have 5 copies of Stardew Valley, though, as that is a game for the whole family.

There was already a bunch of games my brother and I both owned before steam family was an option. But now games I'm only tangentially interested in after he played them or vice versa are much more of an option to quickly play through to see if I like it too. Before, it just wouldn't have been worth buying it to find out. And it's a bonus for the devs too if I do end up liking it, because then I am more likely to buy their next game so I can play it at the same time as my brother.

Gaming is inherently social. Even when we play single-player games, I'm sure most of us have a friend or sibling we talk to about them as we play.