What are the advantages of DNS?

What will be an ideal response?

It allows local control over domain name database segments: This lets servers maintain control over the domain names and related IP addresses that fall under their purview. DNS allows control over distinct portions of the global database for the Internet as a whole so those individuals charged with managing specific domain names and addresses-a role called administrative responsibility in DNS speak - can do their jobs without outside interference.
Data from all database segments is available everywhere. Because any host on the Internet can communicate with any other host on the Internet, name-to-address translations must be available for all hosts as well. DNS makes it possible to find valid domain names anywhere on the Internet and obtain the IP addresses to which those names correspond, among other services. This function is really what makes today's Internet possible.
Database information is robust and highly available. DNS is a key service on the Internet. Without name resolution, remote hosts can be difficult or impossible to access (as anyone who has encountered an occasional problem with DNS can attest). Thus, it is essential that DNS be both robust (resilient in the face of errors and failures) and highly available (quick to respond to requests for service).