My Starkeys have a similar feature built into the TruLink app. I point my phone at the source of the sound and it streams it to my hearing aids. Unfortunately, a smartphone microphone is not designed to pick up high quality sound at a distance.
Also, using an app on a smartphone to capture audio is a fine idea, but it may not be able to pass that audio on to one's hearing aids.
Have you tested this with your hearing aids?
The users at www.tunity.com all appear to be using their headphones. Tunity also claims to work with muted TVs. I'm not sure what that has to do with pushing sound through one's hearing aids.
Can you clarify why you think this is such an incredible app?