The colors can also be lost a bit.
Minority Report I remember reading suffered a bit not really from grain, which as you said it had for effect, but for certain color losses compared to the original image.
JP is like that as well with certain things looking different on the television broadcast and as I said, dark areas having a bit more contrast without having to change the image as opposed to changing the image on the DVD and still not getting the higher contrast.
This is what I was told and was asked to ask around for so That's what I'm doing heh..
I do know however that the bluryness present in JP doesn't need to be so.