I always thought those people would first have some kind of soft touch before making the actual appointment - an intro or whatever. I guess this is complimentary to that, so it's more like a bunch of "offline" things need to happen before this could be used:

1. meet the customer and pitch them on your service
2. customer confirms they want some of your time
3. you send them a link to a scheduling + payment tool in one

OK, I think I get it... basically calendly with Bitcoin. Nice.