As long as there are still buses on regular scheduled routes with timetables its cool. Having to pick someone up who lives in the boondocks can be annoying when you are one of the other passengers. It's nice for the driver and passengers to be on a predictable route, making arrival time relatively easy to schedule, and it's nice for the driver to not have to futz around looking for passengers waiting in stupid locations, or who cancelled last minute.

I think it's best to keep these as speciality services. For instance, I sometimes use such a bus to get to the airport. You reserve a seat a few days in advance, the taxi company running the service figures out the most efficient route based on the customer locations, their flight times and probably some other stuff like expected traffic etc. and will then run the route on the day you need to be there. For this it's great, but might as well just use shared taxis or regular public transport for everything else.