This is extremely irresponsible advice for anyone who isn't already skilled in securing their systems and keeping their software up to date. Skimming through that video, there's no thought given to securing the OS, "pi" account is effectively given root access (through "docker" group) with a default password of "raspberry", network access is unrestricted, there's no thought given to secure remote access (e.g. a VPN), there are no auto-updates for either the OS or vaultwarden, leaving you exposed in case of future vulnerabilities.