First off, you can't cook on the French top like a griddle. It's for pots and pans only. To be fair, I guess you could cook on it but I have no idea how that might work. Definitely nothing liquid like scrambled eggs as there are holes and seams in the top.

What I use it for is to get multiple sauces ready and keep them warm without taking up a burner. You can use the middle to cook or sear normally and them move pans to the edge to keep them warm. You can also remove the center plate and place a wok in it to stir-fry.

It looks pretty cool and is useful if you have a lot of pans going at once that you need to watch without risking burning. That does not happen that often for me so if I had to do it over I would probably get a griddle instead. You can use the griddle in the same way as the French top and you can still cook directly on it too.

My understanding is that most pro chefs don't use the top as designed now but just keep sauces in thermos bottles once they are ready which saves space on the range and opens up burner space for other things. YMMV on all of this.