I am in Vermont, we get 10' of snow a year. Most people have tarps.
The basic difference is that that shrinkwrap is better. Its so slippery that the snow slides off. Tarps need a much stepper pitch.
Seems round here, all the boats 32' + have shrinkwrap, those smaller have tarps. There might be a moolah connection
Having said all that, tarps are fine IF you frame it well. Its very easy to have the tarp "puddle", end up with a 400 lb block of ice that buggers your deck hardware.
Make a ridge with timber (~ 6' high for snow pitch), then make a frame from 1" black water pipe to make a series of "ribs" down the boat. Water/milk jugs are best, and the golfball trick (I use tennis balls).