Yes, it does, in a way.
The fan guard reduces the buffeting around the perimeter of the fans intake side and creates a laminar flow.
The nose cone also helps create a laminar zone in the center where typically there's a dead spot from the hub.
So what you hear is air velocity, not the fan.
Problem is, turbulence cools. So this fan guard will reduce performance by about 6%.
FWIW is a very low drop compared to most decorative guards which are typically 10-15%.
If you want noise reduction, check out my other fan guard:https://www.thingiverse.com/thing:1750976