If you have a Venue with Staff Availability for appointment bookings, users might find it more convenient to have their Walk-in always match what their Booking Availability is set to.
This is where the Walkin & Bookings availability setting can be useful:
Once enabled for a user, whenever you set their Booking Availability, there will no longer be an option to set individual types of availability (Walk-in vs Booking). Instead there will only be the combined option:
Other userful user permission setting: