A control hand is required for feathered paddling in order to change the blade angle; it’s not required for unfeathered paddling. My understanding of the origin of feathered paddles is that they were developed for whitewater racing in order to make it easier for the upper blade to clear the gates. It was later adapted to sea kayaking and flat water kayak racing, probably because prior to the “kayak boom” most paddling instructors came from whitewater backgrounds.
My personal method is to keep my hands loose during the stroke, except in rough conditions where more paddle control is necessary. My upper hand is completely relaxed, with my fingers curling naturally around the paddle as I push it forward. The fingers on my my lower hand _hook _the paddle rather than grabbing it and my thumb curls loosely around it so I don’t drop it when the blade exits the water.
If someone want’s to paddle feathered and likes it, that’s their choice. I would never tell someone that it’s wrong, but the claim that it’s somehow more natural (I’ve seen that argument before) or that it’s a major advantage in wind is bogus.
If you look at the way wind coming from various angles affects paddles and paddlers, it’s very obvious that feathering is only an advantage in a straight-on headwind and only if you use a really high feather angle (like 90 degrees). Simply lowering the paddle angle to get it into the “shadow” of the waves eliminates most of any drag disadvantage of an unfeathered paddle.
I would never teach a new paddler to use a feathered paddle, as it just makes the whole process more difficult, as Oscar points out in his video.