Another consideration, which is probably not an issue for canoes, is a bulky PFD can hamper movement when evacuating. You may notice that in planes, all PFD are inflatable so that you are able to exit the confines of the cabin and then inflate. Also an inflated PFD (or a non-inflating type) could be a hindrance if you wanted to move through water, in a confined area (people have drowned because the buoyancy traps them against a flooded roof).

Probably not relevant to your requirements, but maybe an issue for someone ?