Massachusetts General Laws define three classes of motorized two-wheeled vehicles: Motorcycle, Motorized bicycle, and Motorized scooter. Although the definition of motorized scooter includes two-wheeled vehicles propelled by electric motors with or without human power, motorized scooter specifically excludes anything which falls under the definitions of motorized bicycle and motorcycle. Motorized bicycle is a pedal bicycle which has a helper motor, or a non-pedal bicycle which has a motor, with a cylinder capacity not exceeding fifty cubic centimeters, an automatic transmission, and which is capable of a maximum speed of no more than thirty miles per hour. Motorcycle includes any bicycle with a motor or driving wheel attached, with the exception of vehicles that fall under the specific definition of motorized bicycle. Thus, a pedal bicycle with an electric motor or a non-pedal bicycle with an electric motor, automatic transmission, and maximum speed of 30 miles an hour would fall under the definition of motorized bicycle. An electric bicycle that did not meet those restrictions would be either a motorized scooter or motorcycle, depending on specific characteristics.
There are individuals who claim to have lost considerable amounts of weight by using an electric bike. A recent prospective cohort study however found that people using e-bikes have a higher BMI. By making the biking terrain less of an issue, people who wouldn't otherwise consider biking can use the electric assistance when needed and otherwise pedal as they are able. This means people of lower fitness levels or who haven't cycled in many years can start enjoying the many health benefits E-bikes have to offer. 
There's much less of a sensation of the Electrified S2 'fighting back' once you hit 15.5mph, as well. That's helped by the automatic 2-speed gear box, although this does take some getting used to. Because its cogs are very different sizes you can end up with all sorts of cadence problems as it auto-shifts from high back to low. With practice you can avoid this, or of course you could in theory fit a second cog that's closer in size to the first.