Not only multiple games, but also multiple viewpoints of the same game. Twitch added support for that use case for esports (I think as part of their deal with Overwatch League).

This is a game changer for sports bettors.

Me personally, will probably stick to one video playing in the background. It's more for ambient noise. On days when there are 4 nba games going on simutaneously, I'm far too busy fiddling with my spreadsheet/nba feed to be actually watching the game.