[stefan_]

Crucially a front wheel losing traction isn't recoverable. So it has rained, you ride over a bunch of leaves and that is the moment the electric motor decides to apply power, you're going down immediately.

And why in the first place, there is no benefit.

[dancek]

Well, that depends. It's easy to lock your front wheel for a split-second on gravel without falling---you just need to keep your balance while the wheel is locked. If there's a certain amount of kinetic friction front wheel drive could even make it possible to recover after balance is lost.

AWD (electric front drive + pedaling) is actually quite common among hobbyists in areas that often have snow (say, Scandinavia). It's as useful as it is for cars.

[bhandziuk]

Locking your front wheel is usually 1) very difficult 2) non-recoverable unless you're good on a bike. If you lock you're front wheel going any speed over walking pace you'll probably go down. If you lock it up in the wet you're almost guaranteed to go down fast.

If you're riding uphill rear wheel drive on a bike is great because that's where you're weight is. The front wheel doens't have much. Put power into the front wheel and it might spin.

Put power through the front wheel while going downhill...well there was not need to because you don't need to have a power boost because you're going downhill.

I'm unconvinced except maybe deep snow with big fatty tires.