Check out a 'zip' file to cross port to a system that does not support your VCS of choice (many embedded systems, for instance) and poof half your docs are gone... VCS should store the code, commit messages should aid in bi-secting but should not explain too much other than to clearly document what was changed in that commit with reference to a particular ticket if available. That way you keep the meta stuff in one place and all the action where the code itself lives, and where you are most likely to need it.

I'm a big fan of literate programming, and VCS is not an integral part of that.