Generally it's the latter, and people are just forced to use it. However, I have made an honest effort to try and see the value in it, but the whole concept of trying to squeeze everything into artificial scheduling boundaries via sprints just feels very weird to me. Invariably projects just end up spilling over from sprint to sprint, because even if you manage to break things up into small enough chunks to do a meaningful piece of a project inside of a sprint, then you still end up with leftover time at the end...and then of course you're not going to sit around doing nothing, but rather you'll go ahead and get started on the next sprint's work in advance.

So the ultimate outcome is that you have to follow a certain specific set of prescribed meetings and rituals every X weeks when the current sprint ends or the next sprint is starting, but the actual work that's happening rarely seems to follow a schedule that has anything to do with the sprint cadence.