if you have a retirement community with extensive grounds, I can see the usefulness of that. Perhaps it could work off something like an autonous golf cart.
There is a wrinkle to this idea: Under current law, any such vehicles would need to be ADA-compliant (ADA = Americans with Disabilities Act). Per this, the Federal Transit Administration (FTA) now requires that all vehicles provide access for wheelchairs (and similar mobility aids) for vehicle boarding. (Increasingly this has taken the form of lowfloor buses with out-folding ramps, retained in the floor at the front entrance, that unfold outwardly for wheelchair boarding, and then retract back into underfloor storage.
However, the other requirement is that such passengers be restrained with tiedowns. These must be professionally attached to the wheelchair, typically by the bus driver.
For an automated bus (robobus), this would seem to be a considerably more daunting challenge. In other words, just having an automated golfcart (as such vehicles are currently configured) would not comply. Obviously it's not impossible, but so far, to my knowledge, no automated bus has been designed or modified to accomplish this without human intervention.
Incidentally, rapid rail metros don't have this problem (and a number of totally automated metros now operate worldwide) because passengers board at platforms level with the railcar floor (level boarding). Light rail (including streetcar) systems likewise would be adaptable to automated operation because nowadays the standard is level boarding at all stations. Also, mobility-impaired passengers don't have to be restrained on railcars because the ride quality is far less jerky and more predictable on a smooth, guided running surface compared to buses.