Well, we mostly ride him into combat. Like I said, he's a war elephant. Nothing is quite as terrifying as having a 4 ton animal in gold armor bearing down on you. He's pretty good and smashing through walls, defenses, and pretty much any other obstacle you put in front of him.

[There's not a lot to add here. It wasn't like Hannibal was a magical creature. He was, in fact, just an elephant. An elephant that lived with a bunch of demigods and was used for combat mind you, but an elephant nevertheless.]