There will always be known differences between staging and production, e.g. service names, networking.
The point about staging is that it lets you run risk-free tests on a set of things, in a way that give you confidence about the things that are the same as production. The fact that a set of things works in staging is never an absolute guarantee that it will work in production.
If you are in the position of needing to ship releases rapidly, and you can't run meaningful tests in the available time, then no, it's not useful.