Unless I missed something while skimming this, they're suggesting that you set your password to "something random" and then go on to use ssh keys. This means that a brute force attack is still feasible (if super incredibly unimaginably unlikely). Better still is to use, 'passwd -d -l [user]', which will delete the password (it creates a nonsense hash value, "" I think) and then lock it.

While you're messing about with config files, make sure that "PermitRootLogin" in /etc/ssh/sshd_config is set to "no" (this is now default in most distributions I think), and also add an "AllowUsers [user] [other user] [...]" line thereabouts, which will help to protect you from misbehaving packages or someone attempting to add remote users to your system without your permission.

It should go without saying that if you do all this, and you somehow lose your private key, and you don't have a good backup as the article suggests (for whatever reason), and you don't have some kind of local console access, then you're pooched. Private key management is easy to screw up, so don't scoff. Make sure you have some other way of accessing your machine if you can't get to your private key.