The existence of DNSSEC itself is already a big benefit. Without it, the Domain Name System (DNS) infrastructure would be absolutely vulnerable. Yes! No matter it’s the keystone for the whole Internet to work as you know it, security was not considered in its original design.
The explanation for this lack is easy. The DNS was created in the 1980s, and at that time, the Internet was considerably smaller. Then the “network of networks” grew exponentially, and the lack of authentication was clearly a problem. The Internet Engineering Task Force (IETF) experts in charge of the protocol standards knew it and worked on a solution (the 1990s). That’s how DNSSEC Security Extensions got born.