Cool idea, but only a small minority of people will adopt something like this given that electric bikes seem to be all the rage right now. I can maybe imagine touring cyclists getting into this, but that's it. This would make cycling even more complicated*(!) for most people.

*Probably three quarters of the people I see riding bikes don't even know how to set the proper height for their saddles. They also don't know which roads are appropriate to ride their bikes on, or to follow the direction of traffic, or to not ride on sidewalks. Oh, and no lights at night either. It's no wonder that the US has a high rate of cycling fatalities.