I've been debating this issue in my town as well.
My dreamies so far are 2 snooties, 2 normals and 2 jocks, as well as one lazy, one cranky and one smug, so I'm trying to figure out who I want as my 10th villager and if I'm going to substitute anyone so I can have all personalities. I usually don't go so much for personality type but it does make the game more interesting because of all the different dialogue options and interactions.
But I also feel like a villager's personality is so much more than just those dialogue options. For example, I used to have Kiki and Coco in my town, they're both normal villagers, but I always felt like they had such different personalities! Both of them would talk about nature, learning and reading, but Kiki sounded more sensible, young and a bit naive, while Coco always came off as a more mysterious, nature-loving entomologist or something haha.
I also had that happen with Julian and Kyle, they're both smug. Julian is more of a fashionista, a little bit insecure and cares a lot about people's looks and stuff, while Kyle is more of a ''too cool for skool'' kinda guy.
At least that's what it feels like to me!