Well, the best thing about Dreadnoughts in general is that they are hard to kill, and even after taking 6 points of damage can still do something... but should probably try to GTFO and draw as much fire in the process as possible.
The Assault Carrier has one job; capture the biggest enemy target available. If you do the math, it’s a gamble against an undamaged Battleship, but you can effectively win the game when you pull it off.
I don’t know how much you like to gamble, and you may not know either. If you can, playtest with each in three different games so you can get a feel for each, and you’ll probably capture a Battleship during one of those games.