Conceptually I think this is a GREAT idea. More cargo space, probably much better handling on the bike itself, simple installation, no problems with SLA weight, etc. However I doubt I'd buy one until I rode one or at least listened/read reports from several folks who actually did own one. On the surface it seems low speed severe cornering could be tricky and it's stuff like that I'd be concerned about.
Plus, and this is a big plus, it won't look like an EV bike at all and won't generate the double take from local law enforcement. Maybe.
Mike