However, editor color schemas allow for finer customization. For example, to specify colors for code-highlighting: keywords, statements, strings, ...
Terminal itself would not know anything about these things.
For instance, in an xterm-color or linux terminal, you could type something like ":colo darkblue", and you'd still see custom colors. This is using vim's color path (e.g. "/usr/share/vim/vim72/colors", "~/.vim/colors").
But the colors are there because the text includes things like "make this bold", or "make that green". And in a terminal, I might have customizations for this markup that apply to everything, which can be nice. For instance, maybe I make all bold text red, and that holds in everything from editors to man pages. It's convenient to not have to make these settings in every program that I run.