At least for us, notifications aren't something you can really glance at similarly to app indicators. They're usually text heavy, only really work for longer tasks for readability (which syncing usually isn't), and are always obscured behind another popup for persistent notifications. Persistent notifications also take up more space within the notifications popup, rather than a small icon that you can easily glance at to know what's happening.
As for programs not staying in the task manager, they usually take up less space if open as an app indicator, being able to be passively open but not take up as much space.
We're guessing you're talking about this?