VLC shares the main component that is bundled in CCCP: the libavcodec library.
Note that VLC is a bigger download package.
The advantage with VLC, as with MPC, is that they can use codecs exclusively for themselves with minimal fuss to the rest of the OS.
Of course if you deliberately need codecs to work in a universal fashion across the computer, registering codec packs is convenient. Eg: wanting an encoder, working via directshow, to create video that looks the same, with subs, as when you watched the source video in your directshow-compatible player of choice.