I've often run my registrars separate from my nameservers. Maybe I'm self hosting my nameservers. Maybe the nameservers are tied to the rest of my hosting (for

I've often run my registrars separate from my nameservers. Maybe I'm self hosting my nameservers. Maybe the nameservers are tied to the rest of my hosting (for ease of dynamic hosting) but want the ability to rapidly migrate if the hosting provider goes down. If the registrar is my nameserver host, good luck changing the SOA and NS records when SHTF at your host.