This question comes up a lot.

Since you now surf, you realize how often you use your stern rudder with the paddle. And as you broach across the wave, a good strong brace is often needed. The larger blade will give you stronger rudders and bracing. Many paddlers use GPs for everything and learn to do rudders and bracing totally adequate for surfing. I think you don't see many GPs with surf boats because the surfers and doing what is the excepted best thing for surfing, the big blade. Long boat paddlers are not dedicated surfers usually and use the boat for turing, and occasional surf or whatever.

The concept that the GP can't accelerate comes from people who don't use a GP. If you lined up 10 seasoned paddlers at a starting line - 5 with GPs and 5 conventional paddles, nobody would be left behind in a sprint. Period. As the paddlers move ahead, the stronger or more fit paddlers would slowly pull ahead as in any race. The GP is totally capable of a strong acceleration.