Another answer would be if you are just trading IP address, you're at the whim of your provider to assure that your IP stays the same. Also most web servers run many different web sites using different domain names from one IP. So say you have 1 server with 1 IP, if you use DNS, the web server can serve different websites from the same IP depending on which domain was used to access it. If you don't use DNS, you can't differentiate without using a different path. [like 55.55.55.55/site1 or 55.55.55.55/site2]