It doesn't work terribly well, and most people don't have the bandwidth or monitor resolution to handle it, but future-proofing couldn't hurt.
It may not be the most practical feature now, but we might really appreciate it in the next five or ten years. YouTube, the video sharing website best known as the place you can go to see someone get hit in the groin, has upgraded to be fully compatible with 4K resolution. You've got to appreciate a bit of future-proofing, right?
There are a few sample videos up now, but you'll need a hell of a connection to make them work, and to get the true benefit you'll need a monitor that can handle the resolution.
If you swing on over to YouTube and check out the sample videos, you'll want to select "original resolution" on the selection bar. Then wait for it to load up and hope your rig can handle it.