Service Registry - is it needed?

Question

Suppose you develop a system that has multiple services (implemented by different teams, in different countries, using different technologies including java, php, c#, c++ and more). Let's assume that despite using different technologies, somehow you have agreed to integrate using RESTful APIs.

Does such a system need a Service Registry?

I understand that basically it's not mandatory, since each service may have its own configuration where the service it uses are located. However, creating a central location makes the life of operations easier: they don't need to configure the same service multiple times.

But creating a Service Registry may be complex. It's another system in the solution and it requires resources and even more important ownership. Who will owner it?

I can think about more pros and cons of a Service Registry. So what do you think?