If you assume the cost of a thing can serve as a rough proxy for the energy inputs of the thing then until you meet RoI you're likely negative (environmentally speaking)
casual if the RoI for these is 4-8 years. and some stats[1] show most renters don't stay in one place that long. Given that the majority of people move at least once inside the RoI period, and may not move to somewhere with a balcony that can set up the solar it's possible that more of these system will end up in a landfill than actually help the environment.
which isn't to say I'm against deregulation here. I don't see any real reason to prevent people from being allowed to set them up so long as they're safe. and certainly some people will get great use out of them. but I also don't think they're as categorically great as they're made out to be.