The best reason not to is that it was never made for that
type of water.

Don't confuse the Gulf with the ocean. If someone is simply going a few miles
offshore they are not going to see the pounding waves you see in the ocean
unless there is a storm nearby. In most places in Fla the water will still be
30' deep or so. You can get in a lot more trouble in the great lakes and I
don't see people saying you can't run a pontoon there.
Weather is always a factor on the water, no matter where you run.