It seems as if the coating is vapour-deposited Tungsten Carbide. It is a very hard material commonly used in machine cutting tools. Like all hard coatings designed to increase rim life, they come at a price. The price you will pay is poor wet stopping, poor stopping in high-speed braking and of course noise.
Aluminium is an excellent thermal conductor and readily scavenges the heat generated in the brake pad during braking. That heat is then dissipated into the rim and removed by convection and radiation.
With a coated rim, the heat cannot be transported from the rubber pad. This increases the pad temperature to melting point and the brakes either fail (high performance braking) or the rim track becomes contaminated with a layer of deposited rubber, which squeals like hell. The latter will happen under low performance braking. The industry responds to this problem with high melting point rubber or zero-melt substances like cork and sawdust. However, this just solves one problem - the melt. It doesn't improve braking and doesn't make the noise go away.
A toe-in of the pads on good quality calipers will not help. Toe-in is a cure for flexible brakes which "toe-out" in use and an attempt to neutralize the pad position on the rim.
