It's not a new menu item but rather a london promotion taking place in a single "restaurant" where all the revenue goes to charity.
The whole idea of wagyu is the fat marbling, so grinding it up into hamburger meat makes no sense, and with truffles, you have to have the flavors of the dish relatively simple so the truffle flavor predominates, the same with balsamic (if it's real balsamic vinegar). Here they just threw together all these complexly flavored ingredients probably because of their name recognition, and instead of complimenting, all of the ingredients are competing with each other to make something that won't taste even remotely near the price of the ingredients.
I imagine some schmuck driving up in his jaguar or mercedes convertible, ordering the 200 dollar burger just to show off. But he's a schmuck so he doesn't know that wagyu isn't really worth that much. I bet that's the target demo; wealthy schmucks that dont know better.
I've had Wagyu beef from a farm in Oregon, and it certainly didn't set me back $200. Also, for that price, i really don't want to be eating in an establishment full of obese men with Nascar hats on. Do they roll out the red carpet for you, or what?
Well that's just crazy. I don't think any of the Burger Kings near where I live will be selling any at that $200.00 price tag!
If I were going to pay that much for a meal, the place better be a lot nicer than a Burger King !!!