When I am older and can't pedal as well, I will buy an e bike. For certain types of touring like moderate CC or B&B they would be great. Not everyone wants to knock themselves out physically and they provide an entry into this sort of travel away from cars. I'm all for it. Thank goodness they aren't loud 2 stroke engines or belching oily smoke.
As it is, if I had the disposable cash, I would buy an e full suspension mtb. For downhill parks those things are the cats pajamas!