Hello Brendan!
Yes to Wagyu, when Aldi sell it. No to Kobe.
I think there's a lot of guff at work here!
I stand to be corrected but I believe Wagyu is the strain of cattle, (parallel to a grape being of the Nebbiolo variety).
Kobe beef is regulated as being from cattle grown in a particular delimited area in Japan (like Nebbiolo being grown in a delineated part of Piemonte to make the wine with the protected identity 'Barolo'.)
To me the Aldi Wagyu was less enjoyable than the admirable and IMO underpriced Bavette steaks routinely available in Waitrose...(a bonkersly under-rated cut of beef - don't all rush at once.)
...but as for Kobe I cannot say.
One of the difficulties is that once a type of product becomes esteemed, then charlatans move in to make a cheap buck - in this case by presumably not loving and cosseting the cutie-pie cattle as expensively as was the case when the reputation was formed.
You can quite legally grow Wagyu beef in desperate conditions anywhere in the world, I think. So as with most markets, 'caveat emptor'.
e.g. A friend of mine imports Wagyu embryos from Japan to South Africa, implants them into Aberdeen Angus herds there and sells very nicely direct to high end restaurants in the Cape.
By doing so he makes a lot more money than he would as a crossword compiler! (Though the meat is bloody good, I have to add.)
PS The best steak I've ever tasted was in a Chelsea restaurant called Macellaio - Italian run but the meat was I think from UK... My wallet hurt for weeks mind.
And to conclude the analogy the best wine I have ever tasted was certainly not the most expensive.
So apologies for a unenlightening response to a delicious and simple question!
Regards
M