I put up a giant wall of these in my home and they're incredibly useful. You can build any type of contraption and throw a cleat on the back of it and boom, just put it on the big wall. Reconfigure it every month, build new things to mount up there, it truly is simple and versatile. French cleats truly are terrific.
I probably wouldn't have known if I hadn't wandered into woodworking YouTube - it's a common device for workshop walls, etc., for easily switchable configurations of shelves and whatnots[1].