Implying I don't fully understand the other side of the coin without saying what the other side of the coin is, well condescending. I guess I'm not smart enough for you to "understand"... seriously !
My point is that an upgrade from an OpenWrt partition if initiated from a dysfunctional install may also fail, which alleviates the Known Working State to recover from.
Some, including myself, have put themselves in peculiar situations where the current install is now unreliable/unstable/dysfunctional and the only fail safe way back is via the OEM partition and not via upgrading an install not going well at all, no other disrespect inferred otherwise.
I'm sorry the I don't have the ability to "understand"... Some people like myself are just so dumb...