FYI -SRTA has started this "Uber" type service in both cities. Spotted two of their mini-vans staged in the NB parking lot.
The MicroConnector service is discussed in a little more detail in this article, too. The gist of it appears to be: 1) SRTA started from a place of not wanting to alter their fixed-route bus networks in Fall River and New Bedford, and 2) they instead decided to offer standalone microtransit connections to the cities' stations.
In the case of Fall River, I agree that it doesn't make sense to relocate the bus hub out of Downtown, especially since the city's roadway network naturally feeds into Downtown, but a city of 94,000 people...with a population density near 3,000/sq. mile...with an 11-route local bus network of its own...probably generates enough transit demand that microtransit is not the ideal way to serve a commuter rail station. Since relocating the bus hub doesn't make sense, maybe running an express shuttle between the Downtown bus hub and FR Depot station would.
As for New Bedford, where all routes seem to terminate at the Downtown bus hub, I wonder if through-running a couple routes would be a practical way to expand one-seat ride access to the city's main rail station without upending the existing bus network design. Admittedly I don't know New Bedford's bus system well, but to illustrate the point, maybe Routes 202, 204, and 211 could be matched with 201, 203, and 205, creating a common north-south trunk between Union Street and Logan Street (ignoring the fact that the 211 technically travels on Acushnet, not Purchase).
I don't know what the target percentage should be for bus transit's share of the modal split for rail station access (maybe 15-20% is realistic out here?), but it probably shouldn't be so low in absolute number of riders that microtransit is the most efficient way to serve that cohort. In cities of this size, you shouldn't be expected to drive or squabble over rideshare seats just because you aren't within easy walking range.