I don’t think fighting (hitting things) with soundbending would make sense. Wouldn’t it be more efficient to use plain airbending? The best combat option I can see is using it to confuse and stun enemies. More interesting are the non-combat options: silencing footsteps and conversations for stealth, amplifying sounds to listen in on conversations or send and receive long distance messages,etc. Air monks could also add reverb, phasing, and other voice effects to do something like throat singing.