A well-written villain can make all the difference in a story, but does that mean a complex portrayal of a character who believes in what they’re doing just as much as the hero? Or does it mean a guy with a black hat who’s a horrible bastard?
Intellectually we would probably all claim to prefer the antagonist with depth, but in reality people don’t particularly want their villains to be assorted shades of grey.
The idea of a specific, clearly defined baddie is very appealing. Seeing them get their comeuppance creates a sense of great satisfaction. The more uncompromising the depiction of them as evil, the easier it is to enjoy their downfall or even their death.