I wish they made all games require sharing

Been using this in Beta for a few months now. Very cool

What is this. Because I'm pretty upset that the games I paid for can't be played on different pc's. My daughter wants to pay stardew valley while I'm online with family on satisfactory. I have to take the other pc and go into offline mode. This wasn't the solution. Even with adding members I didn't think I did it right. So does this fix it? Can my family member log into stardew online with her cousin while I'm on another lan game?