Is it realistic to keep a complex system built around functions and microservices in a small organization?
by having a function with a rest API in a container, you can scale it on demand with no infrastructure management
I do have doubts on that part. Well, unless you mean physical infrastructure.
I do believe with docker faas rest swagger, we will have a solution which allows you to write a function, define its input and output with a schema like swagger, define its dependencies with docker, expose it as a service rest, call at scale with faas.
this also makes API discovery and reliability much easier