Famous and high-end gyukatsu restaurants in Japan do use wagyu for beef katsu, but I personally do not recommend using wagyu at home for this specific dish as I do believe wagyu is better served as a simple steak to truly enjoy its unique qualities. In fact, gyukatsu does not need to be made with expensive meat to be delicious, so get any steak meat available in your local supermarket or butcher. It can be made with round, sirloin, or loin meat. I recommend using round meat for those who like light gyukatsu and sirloin for those who enjoy tender and juicy steak.