The first photo is of an $850 part, it's the Spider at the center of a conventional crankset. This Spider is a Power-Meter Spider. It measures the force on the pedals and crank to the drivetrain and is used by avid cyclists. Better electric bikes use something very similar. It is called a Torque Sensor. The signal from the torque sensor is amplified by the motor and put back into the drivetrain. It is like having a throttle that you operate with your foot. Cars use this idea. Push down with a certain amount of pressure and that amount of pressure is amplified by the motor. Bike with this system are not banned from most trails and parks.
Torque sensor bikes do not appeal to people who grew up with things like Jet skis, snowmobiles, and 2-cycle dirt bikes. Torque sensor bikes do appeal to people who are culturally inclined to things like sailboats, kayaks and bicycles. Torque sensor bike riding is totally intuitive, akin to playing a musical instrument normally, yet is amplified. It is all a mater of personal preference.
Having local or relatively local support is very important in my opinion.
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