If a DOMAIN account is the db owner and that account is deleted/disabled (for whatever reason), and Agent Job tied to it will fail, and any database owned by it will still work, but you won't be able to make any changes to it until the user is removed and a "proper" owner is granted as the owner.

If you use a proxy/service account to run things on your server and "that" account is tied to the account then no process tied to it will run (be careful of this one)

IMHO, I would create a routine that updates the db owner to either an internal SQL account (i.e. sa) or to the service account (one that has been set up in active directory to never get locked out))

Pros & cons of having databases owned by sa vrs domain service accounts?

SA

Pro - most likely account will never be disabled

Con - prolly shouldn't tie this account to anything (many people disable it altogether)

Domain Service Account

Pro - external to SQL

Pro - limited access to anything else (if set up properly) but has access within SQL

Con - some nitwit/new hire in IT could say "what's this account for?" drop the account...

😀