They released this in november and it completely went under the radar.
To me, that's a major plus. How often do you have to open lightroom (or any other software) to sort out the pictures that are on your card that are from multiple minor events / shoots... Then go back to the file browser to copy your files in the respective folders of your computer.
Its kinda rare that i'm amazed by a microsoft new feature; but this one really helps my workflow.
And from what I see; the colors of the RAW thumbnail are pretty much spot on. I have to test if the thumbnail takes the .xmp sidecar file (thus the alterations) in consideration tho. That would be totally awesome.