At the moment, Approve Bookings is system wide.
It would be more useful if each service, class or provider could select the option to require approval or allow automatic booking. For my own use: we have the option of dry-hiring a facility or hiring it out with an instructor/coach. When dry hiring it: it would useful to allow automatic booking (so no more human interaction is required). When involving an instructor/coach, it would be useful to allow them to confirm their availability before accepting the booking.
The same principle could be applied to any element of the booking process: services, classes, providers, locations, products, etc.
You could also allow an option to apply system wide or by element.
I currently use approve booking for booking food vendors at our brewery. I want them to all be able to submit their preferred days then I go in to approve the ones I want to keep. I also use SimplyBook for booking regular reservations in the taproom. I want these to be automatically approved. It's a huge pain that I need to manually approve every single reservation.