In our opinion, it is useful to have a different color for each service. In this way, it is visually clearer and more immediate to recognize a day's work. Like google calendar that allows you to customize each task/appointment with a different color to have a more organized and effective calendar!
Yes this is standard with most other apps and makes it easier to view quickly where potential services should be scheduled
This would useful to have as certain services can be combined and some cannot. Color coding allows the booking agent to quickly view the schedule and book or not quickly, without having to read the text.