Barrel break in done right is useful, even for a CZ or a top of the line Krieger or lilja. I bet ya big bag of nickels that there is no hammer forged CZ barrel as smooth as a dan lilja and they recommend it.

If you are cleaning between shots and first one is dark blue with copper, and the 6th one is almost no copper, you are doing something undisputedly. And then you shoot 5 rounds and clean and its dark blue with copper, and on the 3 cycle, there is almost no copper, you are doing something.

Done properly looking for proper things, its very useful.

But hey man, its your gun, do what you want with it.