The whole point of this rig is to be able to use a zig rig in deep water and avoid casting and tangling problems with very long hooklengths. That is what it was designed for - nothing to do with controller floats on the surface. It's simply a development of a setup that pike anglers have been using for a while to present a bait midwater. There is no point in using it in shallowish water.
The bait or foam used only has to support the weight of the hook and a short hooklength, the float supports the rest.
I suggest you don't knock it until you've tried it - it works, and I've caught plenty of carp on it (so have others, particularly on St Johns at Linear where I think it was first used). On the face of it, it would appear to be a helluva contraption to have in the water but the carp don't seem to mind!