E bike? The significant difference would be the actual pedal effort. The more a rider depends on the electric motor, the less the human effort that translates to increases (or decreases) to body temperature.
Helmets provide a safety thing but it also has a cooling effect to allow ventilation to the head and thus the brain (central nervous system).
I would think that E bike riders would tend to flip the switch when the effort becomes strenuous during a ride. Its human nature, having fun without the sweat.
Thus ventilation takes a back seat to the other things when choosing a helmet. When looking at the high priced helmets, its invariably about ventilation and proper fit on various types of heads.