@hamje32 - The point in either case is to reduce the glare from the sun. As the article says the absorptive filter does that quite well.
I remember I went to get new prescription glasses last year. They put some dye or some stuff in my eye as part of the eye exam. They told me the stuff would wear off in a few hours, but that I would have to be careful driving.
They gave me some special sunglasses that I think had the filter on them, because it did a very good job of absorbing sunlight. I drove home with it.
Just out of curiosity, I removed them temporarily when I got home and it felt like I was being blinded by the sun. Clearly the filter had been doing a very good job, so I left the glasses on for an hour or more until the medicine they gave me wore off.