When I looked into Hero a few years ago, my takeaway was the relatively high interest rate vs the much lower mortgage rates.
It seem only suitable for those who couldn’t pay cash or didn’t have a better financing option.
The solar probably still saves money and its probably still a net positive but smaller than if it had been purchased outright or financed with a lower rate.
If a buyer could pay it off early with a lower rate, then much of the downside could be mitigated. Not sure if there is a prepayment penalty but my guess would be no.