Locking a server down to your IP
The most common reason server admins look up their own address is to restrict access. A rule such as ufw allow from 203.0.113.7 to any port 22, a Windows Firewall scope on port 3389, or a MySQL user bound to one host all need the public address shown above, not the 192.168.x.x address your computer reports.
Home and mobile connections usually get a new address after a router restart, so an allow-list built on a dynamic IP can lock you out later. Keep a second way in, such as your provider's console, before you tighten anything.