It's to be consistent so you can use the same layout for pages and for posts if you want.

- [convertible.rb](https://github.com/mojombo/jekyll/blob/master/lib/jekyll/convertible.rb#L100)
- [post.rb](https://github.com/mojombo/jekyll/blob/master/lib/jekyll/post.rb#L252)
- [page.rb](https://github.com/mojombo/jekyll/blob/master/lib/jekyll/page.rb#L107)

Always the same variable for the `#to_liquid` hash