I rarely use this and when I do it is always for some kind of shenanigans. The ball has a pretty small hitting area, so you can do things like ball up right next to them or right over them and go for the throw. For example a close low forward followed by a short ball will end up right in front of them without actually hitting them.
Other than that?? The problem with ball shenanigans is that the ball itself has horrible priority and will lose or trade if they just stick something out, and once you’ve done it once or twice it is easy to spot coming being as slow as it is.
I’ve always suspected you can juggle with a super if you hit with the ball on the way up against a jumping opponent but I’ve never gotten that to work. When you hit on the way up it looks like they go into a juggle-able animation.
I don’t think you can juggle with it, I’m pretty sure the moves that everybody knows can juggle are the only ones that actually can. But hey, it’s not like I haven’t been wrong before.
The parabolic ball seems to be one of those “meh” moves, though. I don’t recall anyone ever really recommending it for anything. I’ve seen it used in combo videos because it can actually hit the opponent up to three times, and then link into something else after Blanka lands, but that seems to require odd circumstances that aren’t likely to come up in a match.
If you hit with the right part of it (animation looks like his cl.st mp), you fall straight down instead of bouncing off them. Then you can combo off of it!