That's not super obvious or convenient for new or casual users. You could make the same argument about images; Just make a new repository (or gist) and put an image in it, then link to it!

This new way is much better.

Since there are no organization private gists [1] you can't use that method for private repositories.

[1] A gist can only be "private" in the sense that it's not listed on the public gist page. No access control takes place once someone guesses the url. That's probably good enough for most uses, but not for all.