In my personal opinion, there's nothing wrong with that, as long as key is not compromised, of course. However, it's somewhat less secure than sudo-enabled acc

In my personal opinion, there's nothing wrong with that, as long as key is not compromised, of course. However, it's somewhat less secure than sudo-enabled account with password requirement. If your SSH key is somehow compromised (unpassworded keyfile or attacker had gained access to ssh-agent's socket, or you've ran a network-listening daemon from your account that had an exploitable RCE) you're a little bit more safe if attackers won't get root access. This only works well for noexec $HOME, of course, as attacker can't mess with your .*shrc and trick you into entering the password.