Back in the day, racers would drill out their chainrings for weight savings. Realistically, there were negligible weight savings, but it sure did look super cool, especially when matched with drilled brake levers. These are our modern interpretation of classic drillium cranks, down to the countersinking. The contrast between black and silver is striking and elegant.
strict lab tests, we have even seen a decrease in aerodynamic drag due to the dimpled surface (like a golf ball). Your results will vary.