Well, first of all, the Dive Ball has a pretty cool animation, so that's one thing!
In Black and White, the Dive Ball supposedly "A somewhat different Poké Ball that works especially well on Pokémon that live underwater.".
Yes, this helps with those bubbly spots in the water, but other than that l guess you could you could say its pretty useless. lt's not even that expensive, and if you care about Pokeball animations as much as l do (:D) than you should consider getting a few of these balls. ~