I outfitted my bike with a freewheeling geared motor to start trying to get more exercise by riding to work. I knew I would never ride to work the 13 miles each way (26 miles a day) without assist. Now I can use more assist on the way to work when I am in a rush, and take a more leisurely ride home using less electric - I end up getting way more exercise than riding in my car and spend more time outside enjoying the ride.

My ride in uses twice as much electric on the way in to work than the ride home when I have more time and want more of a workout (the ride home will use the same if I am lazy or in a rush).
Driving takes 20-25 minutes, riding in the morning takes 40-45 minutes. Having electric made the speed fast enough that it was a workable amount of time.
I just have the throttle control and am able to adjust it to suit the workout I want.

I did not get a scooter because it is noisy, and you can't take it on trails - with my bike outfitted I am fairly stealthy (it is very quiet - my motor sounds like mountain bike knobby tires type hum) and no one notices if I use it on a sidewalk or trail to avoid some streets.

As others have said - it makes me younger - Even with the electric I am still riding slower than some of those racing youngsters!