Why should I really disable root ssh login?

Question

I always read I should disable root login for SSH and login with a user which has sudo. But where is the difference between:

ssh root@vps 

and

ssh myuser@vps
sudo -i 

I don't have physical access to my server and need root permissions per remote access in some way. Is the only advantage here, that the username is unknown?

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Security Tip: Disable Root SSH Login on Linux

One of the biggest security holes you could open on your server is to allow directly logging in as root through ssh, because any cracker can attempt to brute force your root password and potentially get access to your system if they can figure out your password.

It’s much better to have a separate account that you regularly use and simply sudo to root when necessary.

Answer 1

You answered your own question. By disabling remote access to root in *Nix or administrator access in Windows, you make it that much harder for someone to gain privileged access to your computer. If someone steals or brute-forces your non-privileged account password, then they only have limited access.

Answer 2

root is a dangerous account since it can literally do anything it wants on the system. You want to protect it from unauthorized access as much as possible.

By disallowing root logins via SSH, you require 2 passwords for someone to gain root, instead of 1. If someone is trying to guess or crack your passwords, this doubles their workload.

@Daniel B. in the comments is right, using keys are better than passwords, if they are passphrase-protected.

The above still applies if you only allow passphrase-protected keys instead of passwords - and still disallow root from logging in even with a key. So even if you use keys instead of passwords there is a benefit from disabling direct root login via SSH.