One aspect about e-waste is really the size, this has by volume less than an AA-battery, which means the e-waste is pretty much within this realm. For a decently size powerbank, you could have a lifetime of those rings and probably still create less e-waste.

I think it's an interesting approach, in terms of hack-ability a non-rechargable device is pretty much bad - also just imagining that any sort of software or hardware glitch could easily just permanently render the device useless is not super decent either.