Yeah, all of SNK's major fighting games are on the PS2 as part of various "anthologies" and "battle archives."
I still bought Garou Densetsu 2 for my PC-E though just because I don't always have the PS2 hooked up, and its great to have another version of a game you're gonna play that much. Which is also why I own three different ports of Street Fighter II Champion Edition.
Getting back to the topic, I think the deal with the arcade card was NEC was trying to make their console able to compete, spec-wise, with the Super Famicom which was the reigning champion at the time. And perhaps it simply didn't work as well as expected, which is why they pushed the PC-FX instead... which also didn't perform as expected.