What was the Beast Titan's main power?

Im very confused What does the Beast Titan do? Is it just a beast?. Like the Armored Titan, it's armored. The Assault Titan, a strong assault unit. The Jaw Titan, a very strong jaw, The female, a less-stronger than the Assault but faster. But what about the Beast Titan? Ksaver mentioned his titan wasn't usefull in war, so what did his Beast Titan do?