Honestly, just my opinion since I don’t even like celebrity stories anyway.
It’s more of a nostalgia value thing like princess peach or zelda, rather than them actually being particularly pretty. I mean, just my own thoughts...she’s fine. Just..fine. Nothing exceptional that really stands out. But the appeal comes from Harry Potter fans who feel connected and closer to it, which is why celebrity stories usually do well to their fanbase. Those people are already fans of the character/person, so of course they are going to praise it.
In a games sense, we can all name at least four or five hyped up “Oh, so sexy” characters that we think are absolute garbage but just common because they’re from popular well known franchises rather than being particularly appealing themselves.