Time. I use my bike to get to work.
I work 12 hour days. If I rode a manual bike, it would take me 50 minutes to get to work. With my ebike, I can get to work in about 25 minutes. It takes about 18 minute to go by car.
There is still an element of exercise to it. It’s not totally labour free.
Three world tours and 25000 miles, all with my legs which still work great. To each his own.