It helps if they have even small unique features like a pair of bat wings somewhere, but it looks like her little wing is just a hairpin. Otherwise she's entirely human looking since they aren't really even emphasizing the fangs on her art. Very tame after starting with a lamia.
Yeah, if they have buttwings or something it's better, but I don't really see that very often tbh, that kinda thing's usually in the succubus camp. Which, I'm fine with succubi, but I'd still put them (and vamps for that matter) on the tier of like, catgirls, where they're the kinda thing you see in completely vanilla non-monstergirl-centric series. So as you said, just kinda tame/disappointing in the frame of a monstergirl series that starts off with a lamia to have a vamp as the 2nd girl.