Cut-off time is used to disable all the remaining time slots of the same day delivery for specific visitors.
For example, if you have a working day from 10:00 AM to 5:00 PM and you want to get an order for same-day delivery till 4.00 PM. By selecting this option will not allow getting order delivery after 4.00 PM and will hide the time slots for the day and the next day all the time slots will be enabled.
If you have set the minimum delivery interval days like 1 or more days then it will simply disable the same day delivery. In that situation, the cut-off time will not be useful as it’s only used for same day delivery.