I have heard about them. These are brand new. They are probably great alternative to add yellow foil on front lens, like LeMans racers do. Besides that, I'd say they are too yellow to create optimum light. France went away from using yellow headlamps about ten years ago. The color is great in fog, but they are way too bright for fog usage.
However, in the world of styling, pink, purple and now yellow is uncommon and do attract attention!!!
Ichikoh (Japan) has had the yellow-tinted 3200K HID capsules for several years now. Probably not popular here in the US because HID retrofitters seem to want "blue lights". Pity.