I was going to oppose this but then checked the size of all of my notes-- two years of org-mode --and you're right, it's 1.8MB (without the .git).

I did not! :)

Well, then imagine I just suggested it for the image blobs ;)

Even so, I often store images within my online notes. Linking out to them is one option, but of course means that my notes would be dependent upon a third party host. Being able to paste image blobs into the document and store them with the text would be an advantage if I were to want to use this.

I don't think you can paste images into a Markdown editor.

Most Markdown parsers will accept a data:uri blob, as they allow inline HTML.

Do github comments count?

Minor correction: the plain text version is 708 KiB, the ePub version which is 280 KiB uses compression (it's a zip file).

Another nifty datapoint: the plain text of War and Peace is 3.2 MiB