Typically, in comics, you have a penciler, then a separate inker, and then a separate colorist. Sometimes, especially for cover art, there is only one artist.
I like working on all the stages, because it allows me to see more than I usually see in the pencil stage. Little things that help to make a more interesting image.
For this piece, I added more to the cityscape and made some changes to the Kick-Ass Maniac’s costume. All from the coloring stage. If I only did the pencils, I wouldn’t have realized I needed to make adjustments and the inker, colorist may have just followed my blueprints and not added the finishing touches.
I think that the one artist approach is beneficial to the art.