I imagine side by side tests of compressed and uncompressed RAW would have to be made, with images of various ranges of light and shadow,  including print as a primary test medium.

You see, large file sizes are nice to have in working an image for print.  Yet, in print is the difference in "highlight detail" supposedly compressed by Nikon visible to us?   I can believe in the truth of some detail degredation but is this a degredation anyone will see?   I don't have an answer for that one.

I can shoot compressed NEF (NIkon RAW) as fast as the camera will shoot with no problem.
I do have a high speed memory cards but am not sure how much that helps since I have always purchased high speed cards...newer ones simply faster than the older fast ones.