Is the advantage of wagyu and other fine beef obliterated when formed into minced burger patty?

The main thing that wagyu is supposed to get you is dense marbling. That's especially important for cuts low in fat, like the filet and the sirloin. That is, steaks.

The rest of the cow has to go somewhere. The parts that get ground into burgers on conventional cows might as well go into "Kobe sliders". There will be some differences from conventionally-raised beef, where the ground meat is usually made by combining fatty cuts with lean cuts to achieve a precise fat ratio. I would expect ground wagyu to have more fat than a conventional burger, and to have the fat incorporated somewhat differently, but it will vary from processor to processor.

So I'd say that the advantage isn't obliterated, exactly. I'd just say that a wagyu burger will be a lot more like a regular burger than a wagyu steak compared to an Angus steak. There's nothing wrong with that, at least as long as they're not trying to charge massively superpremium prices for it. (In my experience they come with a modest upcharge.)

This article is disputed by others, so consider it one person's researched opinion and take it as you wish I think: http://www.seriouseats.com/2016/07/fake-kobe-wagyu-beef-japanese-steak.html

The general statements are that almost all claims of anything severed as Kobe or even Wagu are likely false or misleading. Now, the author makes his money by writing about fake foods, so has a vested interest in such claims, so that should influence merits, and saying something is a Wagu slider that was made with part or all US Wagu, is that fake food, misleading, or honest? Your call on that.

But, personally, I think you probably made the correct call. I would expect something called a Wagu slider would be one that might have some amount out Wagu trimmings added, but not enough to really be the correct us of the meat or representative of the name. The same went on for some time with Bison meat, a wonderful alternative to beef if properly prepared. But for years, it was difficult to find anything but tourist stop samples as over-cooked burgers and meatloaf that was likely about 10% bison and gave people a very poor introduction to a fine meat. That also is opinion, not backed by evidence other than person anecdotal experience though, so no one yell slander please.

I'm a carnivore who eats 2 lbs of beef a day.

As someone who started consuming wagyu ground beef (sourced here) on daily basis, I can confirm that there is a huge difference in the taste compared to conventional ground beef.

Marbling is not the only factor. Remember that much of the meat flavour is in the fat.