I believe all the 05 and newer cars have that style.
I've never heard an explanation for it, but I assume that it's largely for safety.
I know that the headrests in my 97, which are basically in line with the seat back, puts the headrest significantly back from my head.
Their purpose is to prevent whiplash but I've tried to rest my head back against the headrest while driving and there's no way I could do that with any comfort.
In other words, I'm pretty sure that if I got hit in the back, I'd end up with whiplash anyway.
I'm surprised she says that her head hits the headrest. I think the designers would have kept it just barely back of where it touches your head.