Since glue records already provide the IPs of each NameServer, why are A records pointing to the IP of the NameServer still required on the server itself?
For example :
Q: "I am trying to find domain.com. What is the IP address for the website domain.com?" A: "I do not have the address. Check the name server for domain.com. You will find the IP address there." Q: "Okay. What is the name server for domain.com?" A: "ns1.domain.com(127.0.0.1)"
The parent zone (com) already provides the IP of that nameserver, I can't see why an A record is required.