i used to religiously wear a snorkel on every single dive in every part of the world, because my original NAUI instructor said to. Then, when the paradigm shift caught up with me, i was used to swimming on my back (and making a beeline for the boat was never a problem...just use the sun, clouds, landmarks, compass for a reference point). Also, i had never had a problem with the thing snagging in the kelp (which we have a lot of in So Calif). Big water is not a problem either, as i just ride up and over the swells on my back.
one day, when i finally did leave the thing home, a big 250 pound Napoleon Wrasse was hanging out under the boat for a half hour snarfing the chicken bones that we were throwing overboard. It was then and there that i realized how much you miss something when opportunity swims by! Now the snorkel stays on the boat, but at the ready.