Because it's got two universities (Brighton and Sussex), plus countless language schools, Brighton is very much a young person's city, with a lively vibe to it (although I love it too, and I'm far from 'young'!).
It's got some fantastic bars including the totally wonderful (and appropriately named) Queen's Arms, where there's live cabaret 10 times per week, featuring some the very best (and most outrageous!) drag acts around ;-)
Wanna dance? Brighton's certainly not short of nightclubs!
https://www.designmynight.com/brighton/clubs/best-brighton-clubs
I thoroughly recommend Brighton but I simply don't rate Blackpool at all.