The brain is good in regulating signals it receive.
But recognizing a signal, amplifying it in a way the entire brain / system can use it and transform itself, is much more difficult. In a way, it requires awareness.
A Biofeedback system, if works in a way the it feeds back a meaningful signal back to the brain, is an equivalent of a cane or any other facilitation that allows this new neurological movement and process to take place.
Its a sort of magic.
Go to the source.
The origin of biofeedback in the 50's is more exciting than the current biofeedback, neurofeedback, biohacking all combined.
I encourage you to listen to Ph.D. Joe Kamiya