About DT's point about needing the systray for nextcloud, I think it's valid. That's not to say that OBS doesn't need a systray but that nextcloud definitely needs one.

Most of the things you do on the nextcloud app you do through the systray. In most cases you use the systray to just check the status of things. You can also log in and set up sync settings but it's a very limited app. Instead other things are done in the webapp, or by file operation in synced folders.