Suppose I have amule running and for some reason I have to quit my X session. It would be nice to have a way of turning the current instance into daemon mode, so I don't have to start it over again.
I might be wrong, but I guess when you restart amule you loose the time you have been waiting on semeones else queue, right?.
For the inverse (turning a running daemon into gui mode) you can always use amulegui, but it would be nice if I could also bring the daemon into full gui mode, since there are some features amulegui doesn't have, like the systray icon or files comments.