I mean...is it? I don't really get what to be upset about here. If it were really DLC sans game, then yeah, that'd be ridiculous, but if people want to buy these things, why not? And $10 for both seems like a decent price, tbh.
I dunno. I just don't see it as a big problem, I guess. Just because it has some useless stuff attached doesn't mean it's a scam or something, as long as the artbook and music is accessible and are considered worth the price.
Also, looking at the pack, the "dlc" is 4 whole cosmetics. If it's considered a scam without those, then it should be considered a scam with them.