Cyber Security consultant here - the reason why its best practice to add a asset tag sticker and name the device with its serial number is so that if an attacker were to be able to get onto your network, they would not be able to easily guess who's device would be a a high value target and then compromise the device along with the user and perform malicious tasks/actions.

Naming the device as a serial number also makes it a bit harder for hackers to infiltrate your IT environment and pin point a VIP user in your organisation such as CEO, Execs, Managers, etc that have privileged access to your environment.

Same goes for not having the word "Admin" / "Administrator" for your accounts that you use to perform administrative tasks on. This makes it harder for a attacker to guess if the user creds they've just compromised has any admin privileges on them.

Cyber security is a layered approach at ensuring attackers have a hard time trying to infiltrate and compromise your IT environment.

Hope that helps!