Good for what? Security thru simplicity. It's easy to make copies in postapocalyptic world, where you have only a typewriter. You don't need fancy tools to view it. Anything else?
The second part is here, because I recently read too many RFCs, which were devoid of examples, explanations and hyperlinks (right, plain text). I had no other ideas why is it that way.
Which is a good thing, most of the time.