If you practice separation of concerns and design your interfaces well, I feel the debate is moot. Who cares if your authentication (micro)service is running lo

If you practice separation of concerns and design your interfaces well, I feel the debate is moot. Who cares if your authentication (micro)service is running locally or on it's own remote cluster as long as it implements the same interface? Clients to the authentication system don't need to know how it works, just the interface. The team responsible for the authentication system can work in parallel and publish new versions as a library that can be imported by clients. I unfortunately don't have the need for a distributed system right now. Does anyone with more experience care to elaborate?