It's on an encrypted disk image. Unless it's mounted, no one's reading the .rtf. The color obscurity isn't securing against someone getting the passwords, it's security against casual observation. That's pretty clear for anyone who didn't skip reading the first paragraph.

Keychain isn't very portable and it's pretty clunky for copy/paste use when you're working out of a terminal. To copy a password out of Keychain Access, you'll be entering a password for each one of them. Not only that, but there's no way to obscure the usernames in it either. Now, if there's a terminal app that can hook the keychain for passwords when you're connected to other servers, that might be something. But as is, it's a poor solution.

Frankly, I find it to be a lot more ingenious of a method than my previous "write 47 passwords on a tiny card" one.