The argument here is that microservices are another level of code reuse, with their own encapsulation.
But microservices are also about coupling: just have a self-contained service that does one thing.
But microservices are also about coupling: just have a self-contained service that does one thing.
What stops you from creating a module inside a monolith with an interface that provides a self-contained service that does one thing?
You have a problem. You decide to use microservices to solve it. Now you have ten problems.