Aut cum scuto aut in scuto
Seems like a handy portable idea, but I've seen a winch cable snap before, and I'm not sure I'd prefer to be standing where that hand throttle is. Might be good for light stuff well below capacity, i.e. with a paranoid safety factor.
A hand cranked version would be better, it's kinda hard to find a 110vac outlet on a tree or on a cactus, or boulder.