Well ... It is a great discussion topic here in Denmark too. Almost religion.
But you are right, the majority are white to hunt for open water. But if you are between stone or reeds, most people have a caomplage on their layout boat.
It is my belief that ducks can be shot with good results, almost regardless of the color of the layout boat. The layout boat I have seen is all white, green or different shades of gray from very light gray to gray. Others have been a mix of white, gray, black and camouflage structures in different colors.
My layout boat is matt white. Have had another layout boat like yours in gray and started out with my Jafi being light gray. Different hunting experiences where other hunters and layout boat were white made me paint my Jafi mat white.
And I now have clearly the best in my white clothes and layout boat.
I have a little theory explaining why my layout boat is white to the open water. Haven't even heard or talked to others who could convince me that it didn't.
Should I occasionally lie in surroundings other than open water then I blur the layout boat with the naturally occurring materials on the spot.
That's why my layout boat is White
The little theory
Some years ago when my seaduck hunting started I borrowed layout boat and decoys, this happened on Nissumfjord. layout boat was gray. Nissumfjord is a very shallow fjord with very large area with shallow water
One day after I had been on a longer hike, due to a winged duck, I experienced that almost could not find back to layout boat. Couldn't quite see it. It was the decoys I saw first.
So does it work the same way with the ducks when they arrive, then they do not see layout boat before they are very close, but then get an eye on layout boat and have a lot of focus on it, bad for us hunters it can cause bad shot chances or none at all.
The white layout boat is very much visible even at a long distance you can see layout boat, and so can the ducks. But the white color is not a warning color on the water so the ducks are aware of it from afar and are aware of its presence throughout the flight into the lures, but are not afraid of it.
So in my theory this can give more, good calm chances.
If you can lie still, as it is the all-shading factor for getting birds on the deck.
If the layout boat is gray or green and the hunter is white, then it is the hunter who stands out, and that is not the intention.
Both situations are in shallow water.
Here it is on open water.
Here it is between stone and seaweed, so the layout boat is camouflaged. With Tobis fish nets and seaweed,