While they don't solve the problem, they extend the service-life of the headset by over 10x over ball-bearings. And the races are replaceable, so at that 10x longer service-interval, you just replace the lower bearing-race rather than the entire headset.

To give the OP more data on efficiency and following up on some other's post, here is where rider's energy is expended on a bike at various speeds:

Note that bearing and tyre-drag represents a smaller and smaller percentage of total-drag as speeds increase. That's because drivetrain-drag goes up linearly with speed while wind-resistance goes up to the square-power of speed and the power-required to overcome that wind-resistance goes up by the cube-power of speed. In order to go twice as fast, you need 8x the power to overcome the extra wind-resistance.

Most effective way to improve your power-output's efficiency is to combat total aero-drag: A*cD. With traditional bikes, one can improve A*cD by tucking in as low as possible. Even with trained cyclists, there's some loss of power-output, but is more than made up by the reduction in aero-drag. You can get even better reduction in A with recumbents, and total-drag can be only 50% of an upright bike. Once you've minimized your A as much as possible, you start playing with cD by using fairings. These aero mods will increase your speed for the same power much more than any improvement in drivetrain-drag.