I found this out yesterday xD. The moment I found this out, is the moment they became dead to me. The only useful thing, that's always useful. Is they are a point seeker, that you don't have to spend ink on. It'll reveal the enemy position if you pressed and held the launch button prior to them submerging in ink.
I think bunny hop, would be a better word... even flop. You can just flop over them. :D so if you are killing them and they fire this, you can pretty much kill them uninterrupted.
Ink seekers are excellent if no one knows it is coming. But I'd rather have the ink mine. Because no one ever knows they are coming. You have to actually have a perk to see it, and it doesn't mean you will always see it, if I place it out of site, being obstructed by an object