I think it was mostly about money, every body who had a pc engine could play a hucard but not every one who had a pc engine could play a super cd or arcade card game, and SF II was the bigest name around at the time.
SF II was a 20 meg game, Flash Hiders and Godzilla for the snes were also 20 megs, i think the super cd versions of those two games were if anything better, so i think a scd version would have been very good and a ACD version of course would have been awesome.