Originally Posted by happyvalley
By definition, some pedaling will be inherent with all motor assisted bicycles, being single speeds, at starts, out of corners, on acceleration etc. In a sense, gearing matters more than engine choice and it depends if you want low end torque to easily get up to a modest cruising speed or pedal more at the start to attain a higher top speed. More than that and a scooter or motorcycle starts to make more sense.
To clarify: your definition may be true with motor assisted
bicycles, which is one reason why we prefer differentiating between the terms "motor assisted bicycle" (usually reserved for under 1hp or less and/or pedalic only systems) and "motorized bicycle" (general term for a bicycle with any type/size of motor). Deciding that a scooter or motorcycle makes more sense than anything other than a limited "assist" system is a matter of personal preference and not specific definition in this instance.
In actuality this isn't relevant to the question at hand as in the OP's home state of Montana there appears* to be no such "assist" restriction, gears are allowed so long as it's an automatic & it seems in Montana, a moped falls under the definition of a bicycle - pedals are only required to be exempt from registration if you would so choose.
Which means should the OP wish - he could build a multi-speed 50cc/2hp motorized bicycle with an automatic or variator-style transmission and would be completely within the law & has been proven by any number of mopeds, pedaling would be at the operator's discretion, if at all.
*please confirm your local area's laws for yourself, I could be mistaken