I'm not an owner, but I suspect there will be a clutch mechanism that stops the Bafang from offering resistance when not driving the bike.
Ah, could this be why the STEPS chainring freewheels? I got caught out by that when applying some chain lube (which is surprisingly tricky when it freewheels at both ends)...
I don't know the Bafang.
The Bafang has two freewheels. Either the motor can move without the pedals, or the pedals without the motor, so there is little added resistance in pedalling motor-off. I suspect most BB systems are the same. Allowing the motor to move without the pedals is what makes applying chain lube tricky, but it makes sense if you ever want to use throttle control.
The only exception I know of was the original Stokemonkey, which drove through a tandem chainset. People used to riding fixed loved it; everyone else bashed their shins.