A "comfort bike"? I am not up on all the modern terminology....my boss yelled at me because I called his 800 dollar road bike a "10 speed".
He said "You obviously don't know ANYTHING about bikes." (yes, he's a leg shaver/spandex elitist who rides a couple dozen miles a year)
Anyhow, once you fit a bicycle motor to a bike, it becomes a motorized bicycle...and I do know a thing or two about those.