Getting a new pair of nameservers doesn't always mean the provider has finished setting up your domain. For .de, DENIC checks that the servers are reachable and already answering authoritatively for the domain before accepting the change, which can catch a missing DNS zone. Would you find this useful when moving a website, or not at all?
Yeah that kind of pre-check sounds genuinely useful. It catches the classic mistake of pointing a domain at nameservers that aren't serving the zone yet. Still worth lowering the TTL a day before and querying the new nameservers directly before you switch.