An interesting side effect of this low-level bit mapping is that various banks authorization logics can be manipulated to increase auth rates by subtle bit flipping across various fields.
All the big fintech companies have ML running over changes to identify what results in the highest auth rates on a per bin basis.
I would be very surprised if bit flipping and ML were really used here, do you have any source?
While for sure there's a lot of signal and value in monitoring auth rates per BIN per payload, flipping bits can be extremely disruptive and counterproductive. From doing the wrong operation to being fined by the schemes, it's a lot of risk for not a lot of gain when these fields can be tuned ad-hoc for the few card issuers that deviate from the standard/norm.
All the big fintech companies have ML running over changes to identify what results in the highest auth rates on a per bin basis.