You can keep Instant book on and have your settins so you do not have accept same-day or back to back bookings through your "availability" settings. You can also require advance booking to the number of days you need to avoid running yourself full-tilt boogie hosting.
I use these features because it is too hard to turn my properties for a guest checking out then another checking in the same day - no back to back.
Also you can change instant booking to meet more requirements than Airbnb's minimum. It keeps those travelers without ratings from instant booking without your approval and you do not loose listing position.