In domain configuration at CloudFlare, the DNS section stores the record definitions. What is the exact purpose of NS record here? If configured, it shows something like:
Type | Name | Value | TTL
-----+------------+---------------------------+----------
NS | domain.com | managed by ns1.domain.com | Automatic
But the NS at authoritative DNS server (registrar) is configured accordingly to the CloudFlare assignments:
adi.ns.cloudflare.com
bob.ns.cloudflare.com
And the latter are presented if the domain is queried for example by any DNS propagation checker (e.g. whatsmydns.net).
The domain is being managed by their DNS anyway, so what's the purpose of defining the NS records in CloudFlare configuration panel?