Recessed cockpits were started by Valley Canoe in England. The intention was so you could reenter the kayak in an assisted or self rescue and avoid snags of the PFD or any other safety stuff attached to it. They were into the hard core kayaking long before Americans even knew how to do a rescue. All the other side benefits like ease of rolling etc. just fell into place. I think it's also good industrial design like recessed hatches and bungee fittings. (All came from Valley Canoe)