What would be a practical use of the
 

color correction features?

Do you mean the "color painting" feature? I tried it in the hope that it would allow to replace one color by another, but it cannot completely change a color (like replacing a blue by a red). So the only practical use I have found for it is when people are lit by different lights, you can make that a little less obvious.

Example: some time ago, I filmed a concert an one of the artists was under a red light. I selected that color and turned the red gain way down. In the movie, that artist is still red but the result is less extreme.

I would imagine that it would give perfect results for a mix of natural and artificial light.

I did not find any other pratical use for it, but I am willing to listen...

I think he means the "Color correction" feature.

I've yet to use the sky detail, skin detail, and color correction features.