I have to agree, pits brought a real purpose of use for Frostbiter into battle mode. Actually I'm starting to think it's one of the most gimmicky weapons... Let's see what it can do:
-good for race games
-freeze players in mid-air to make them lose momentum and fall
-bounce off frozen enemies by running into them
-freeze platforms to make them stop spinning or swinging
-after shooting a speedless platform to swing freeze it at highest point to reach a ledge
-freezing a witch makes it much easier to kick or punch her
-freeze a spring to pass through it
-freeze a box, rock, morph or powerup to make it move by itself once pushed, so it can be pushed off ledges and then move from the wall to be pushed further

What else? I'm sure I missed something.