I disagree. Firstly, I've always thought the Supergrafx looked sexy. But considering I found one, boxed, for £70, that's not much more than a Core console (roughly the same) AND it can play those 5 games. One is too expensive for me, but Daimakaimura is good, and I quite like Granzort (though it's confusing).
So basically, there's no negative over a core unit*, unless you already have one.
*apart from you need a RAU-30 for a briefcase setup - just get a Super CD-ROM 2