You don't need one. It's a cost/benefit thing - is it worth having one? Do you really need to use Vim or Emacs or Eclipse, etc? You don't need to.
I can imagine some reasons why it might be useful to have it as a plugin. Making a plugin means giving it a name and a URL (and if it's on vim.org, a place in a well-known directory), and that makes discovery and communication of its existence easier. The fact that it's useful to have a gist for it bears this out, I think. I can't think of why it's that bad a thing to have a plugin for it.
I can imagine some reasons why it might be useful to have it as a plugin. Making a plugin means giving it a name and a URL (and if it's on vim.org, a place in a well-known directory), and that makes discovery and communication of its existence easier. The fact that it's useful to have a gist for it bears this out, I think. I can't think of why it's that bad a thing to have a plugin for it.