A year ago I would have agreed with you, but these days I love my electric mountain bike for a number of reasons. Biggest reason is it let's me choose how much effort to put in. On easy days I can do the same loop as harder days and just use a little more battery. If I'm running errands in the heat I don't have to be sweaty. It was also really useful when a friend crashed in the woods, enabling them to ride several miles back to the car (albeit slowly) without pedalling/walking.