Correct. The higher you go in Kelvin temp, the less usable light you get. It might look just as bright to your eyes when you look at your lights, but in situations where there is rain, snow, certain lighting…you’re getting less usable light by getting blue, purple, green, etc. HID’s.
My rule of thumb is 6000k and below. Nothing more. 6000k is still pretty good in terms of usable light and it’s not an obnoxious color. I have a 55w kit which washes out the color a bit, so mine look white with a very light hint of blue.
As far as glare/HID’s goes…every head light is different. Some glare more than others with HID lights. My generation Maxima, for example, glares BAD. This is why I have projectors retrofitted into my car (Acura TL Bi-Xenon projectors with a replica ZKW lenses).
Personally…unless my car comes with HID projectors stock, I will always be sending my headlights out to get retro’ed. When I drive my moms Subaru or my dads 92 Chevy, I can’t see crap. Properly working/setup HID’s are such an improvement in night safety.
My cut-off pictures:
Low Beam:
Low Beam Cutoff Other Angle:
High Beam:
Projector itself: