I will say way less stupid than bleeping solar roads.
No need to deal with loads, the panels angle can be set optimally, if the panels are mounted on a floating structure, even do east-west tracking simply by tugging on the anchor lines. Provided they can reuse the transmission lines from the windfarm, that is a less costly proposition. And I do not think they'll have to pay anything to park their farm on the sea. These things can be built on land and towed to their final position.
No idea what it takes to make panels resistant to a marine environment, the North Sea is really a harsh place, and maintenance can be an issue, but training a seafaring windmill technician to work on a solar system doesn't sound like something difficult.
From my perspective as a land dweller, I do not see any reason why someone would want to go through all that trouble, but I found some pros at least...