Group Session was recently added to Spotify and it seems like a wonderful feature so far. Unfortunately, it is only available on mobile and tablet so those of us who primarily use the desktop app cannot use it. Please include desktop users in the party!
The current method of starting a Group Session (scanning a code) is obviously catered to mobile phones, but it seems that an alphanumeric code could also be provided, which desktop users can input to join a group. I believe an alphanumeric code would be nice to have overall because it is easier to use if we aren't right next to each other (i.e. social distancing).
One final note: Of course I could just use my phone if I want to join a Group Session, but I greatly prefer the experience and UI on the desktop app and I believe it is better suited for adding songs to a queue (as you do in group session).