That doesn’t help with rolling out updates to the DNS for company.com which is the point here. It’s always DNS because your pre-production smoke tests can’t test your production DNS configuration.
If I'm understanding it right, the idea is that the DNS configuration for company-staging.com is identical to that for company.com - same IPs and servers, DNS provider, domain registrar.
Literally the only differences are s/company/company-staging/, all accesses should hit the same server with the same request other than the Host header.
Then you can update the DNS configuration for company-staging.com, and if that doesn't break there's very little scope for the update to company.com to go differently.
The purpose of a staged rollout is to test things with some percentage of actual real-world production traffic, after having already thoroughly tested things in a private staging environment. Your staging URL doesn't have that. Unless the public happens to know about it.
The scope for it to go wrong is the differences in real-world and simulation.
It's a good thing to have, but not a replacement for the concept of staged rollout.
