Bright new engineers don't know he evolutionary history of a product and often repeat design errors the old timers learned from years ago.
It's important to know if a design element was there for functional reasons, esthetic reasons or to make it easy to manufacture. And even if functional, was it an arbitrary choice out of a number of seemingly equivalent choices. No one really documents the hows and whys of design choices.
This reminds of the story of the Soviets cloning a B-29 that crash landed in Siberia after a bombing run on Japan in 1944. The first Soviet copy (called TU-4) included a replica of a patched bullet hole. Obviously, no one wanted to risk saying they understood the original design.