Is it really 'falling' for it if you're self aware and you don't give a fuck? You like what you like. I doubt your friend is actually some dullard idiot like the way you seem to be phrasing it.
I mean, he didn't care that Nier Automata was a good game, he just saw those ass images and decided to buy it. He also bought THIS game for the same reason (and that was a shit game). I mean, he's my friend (and a very good one) and I don't think he's an idiot, but I don't know how else to call it except for "falling for it" if you buy game due a hot girl in the cover or the screenshots.