I think it's safe to say they're charging for it because they haven't raised the money to develop and manufacture the thing.
Yeah, there's potential to use a device like this to build a service like Simple or Moven but without the need to force users to open a new account with you just to get the necessary data. They even showed the instant feedback alerts in the demo video.
For users, this must be some retro fad jumping the gun. Given the value of the transaction data going through this thing, it should be free at worst.