As far as I know yes, it works by reducing appetite. So there definitely is the risk of just bouncing back after one stops using it, assuming nothing else has changed.

That said, this doesn’t necessarily make it worthless. When treating something like depression one might also prescribe something that improves the mood to support psychotherapy to treat the underlying causes. In a similar way losing weight first through medication and then having therapy alongside it or starting to do sports (that gets easier to pick up with lower weight) might improve treatment outcomes.

And theoretically if it were cheap enough and without longterm side effects, then I could see a scenario where taking it permanently could still be better than the detrimental health effects obesity has.