If this becomes a more prevalent trend the insurance rates on Prius cars will go up. So then they might “save” their owners a little on gas over a few years compared to a similar non-hybrid car, but the increased insurance premium will make up the difference.
We had a similar discussion here a week or two ago. Depending on how much you drive, and how long you keep them Prius cars often do not “save” their owners any money at all as compared to other similar sized vehicles. This trend will only make it that much worse.
Garages have a special kit of bolts for the Prius battery that cannot be unscrewed replacing the existing bolts...like the special wheel lug nuts with a key.