The question is whether the body spends any energy outside of that hour after exercising (e.g. by growing muscle, etc.) than it would otherwise. That would make exercise more effective when considering longer periods of time.
It helps in other non-measurable ways too.
If you know you're going to go for a run in 2-3 hours, you're going to not eat an entire pizza for lunch, for example.
That's not the only way it helps. It tends to curb appetite.