"Yup they created it to be discrete in order to manage within the block as to not discard the whole thing - correct."
Yes
With that, bad cells of the memory, as managed segments(737), are held in check through the same process. In doing that, they do not have to discard a whole block as was previously done and the Microcontroller/firmware knows not to write data to the bad segments.
This was initially purposely conceived in order to utilize bad memory...it all morphed form there to where we are.
doni