[rudra]

edit.
i just got the best link for you (and me too).. here

https://webmasters.stackexchange.com/que...ameservers

just please go have a read and make sure you read the comments too.


it simply exposes your ip to attackers among other things. attackers , even small time ones, can shut down your site with impunity even if you use cloudflare to hide behind.
also big dns hosters like cloudflare have multiple servers positioned worldwide in various geographically dispersed locations. so it is always the nearest set of servers that answers the dns queries. so impossibly harder to take down by simply taking a simple point. like they would for yours by taking down your vps.

also I always thought it was more silly than funny to ask top level servers for the authoritative name servers for mysite dot com and get that it is at ns1 dot mysite dot com with the ip as myip.

lol... mean a subdomain holding records for the domain... gaah
(though it works cause the reply contains the ip too from an A record passed on by the parent zone for the subdomain... otherwise it would be kind of circular)
apparently it is the case for almost all top levels as the respective zones reside on a subdomain... Read the above link.