Sounds like something we tried in Helsinki metropolitan area 10-15 years ago. I think it was shuttered due to low demand. Existing paths were already following population density, so there already was maximum availability for bus users.

Where I think it is most in use as a separate program is picking up elderly people. Retirement homes have minubuses picking up people and driving them to centrew and back. The users don’t have to abide by a busier standard bus schedule and the bus is more accessible by the elderly.