The problem I see with the bunjee is that it's too short. Put 50-feet of nylon rope on it and you may have something useful. The towing vehicle has to be able to get up some speed for that inertia to be converted into real pulling power.
Not if you use a sno-bunjee.
I'm sure everyone has thought that the sno-bunjee was a gimmick, up until they actually seen one in action. They work, plain and simple, and I don't need to do an experience with rope followed by a sno-bunjee to know that. I've been around countless stuck snowmobiles. Short tracks, long tracks, deep lug tracks, wide tracks. Playing in the hills, playing in the power, stuck in holes, stuck in brooks, stuck in slob. Stuck with a crowd of people, with a partner, and stuck all by myself. I've used my hands and feet to dig out, I've dug with shovels, I've done the rope through the track trick, rope to a sled, ratchet straps. I've used the bunjee by myself, tied to a tree, pulled by hand, and had it hooked up to sleds.
There's no way anyone with extensive snowmobile experience would say that a sno-bunjee doesn't work, because they do. You might not understand why they do, or believe that they do. But they do.