Online booking is worth it if you sell time rather than jobs: barbers, salons, lash and nail studios, massage, driving instructors, anyone with a diary of slots. An empty afternoon slot is gone permanently.

The argument that settles it is when people book. A large share of bookings are made in the evening, after work, from a sofa, at an hour when nobody is answering your phone. Those are not calls you missed. They are calls that were never made, because the person would have had to wait until morning and by morning they had booked elsewhere.

If you quote every job individually, booking is the wrong tool and a good quote form is the right one.