I am pointing out that if every unique binary never before run/approved is blocked, then no developer will be able to build and then run the software they are paid to write, since them developing it modifies said software into a new and never before seen sequence of bits.
OP may not have meant to say that "it's good to have an absolute allowlist of executable signatures and block everything else", but that is how I interpreted the initial claim and I am merely pointing out that such a system would be more than inconvenient, it'd make the workflow of editing and then running software nearly impossible.