Hiding a brake calliper from the wind is an effective way to make you faster.
There are basically two locations for a rear brake: seat stays or chain stays. The chain stay location obviously works well aerodynamically, but can be a challenge to service unless you have a reliable, low-maintenance hydraulic brake. In contrast, it’s easier to simply shape the seat stays to hide the brake from the wind.
The benefit: Hidden from the wind, not from the mechanic. Faster and easier.