PersistentSubscription with InFlight 1

If you create a Persisten Subscription and set InFlight to 1 (and AutoAck to false) what are the differences (if any) between that and a catch up subscription?
In my head, both would replay in order, one at a time.

The only thing I can think of is, the consumer would be responsible for deciding what happens if an event can’t be processed (maybe it’s ok to carry on, or stop the subscription)

If there are no major differences, it would mean you could have a “catch up subscription” visible from the UI (which makes it much easier for supporting)