Those boundaries also increase the cost of development. If you are institutionally incapable of enforcing coding standards such that you can't prevent juniors from coupling your modules, perhaps it's worth it. But there are more efficient ways to build and run an engineering organization.
The best place for such boundaries is at the team/division/org level, not team-internal or single dev-internal like microservices implies with its name. Embrace Conway's law in your architecture, and don't subdivide within a service.
The best place for such boundaries is at the team/division/org level, not team-internal or single dev-internal like microservices implies with its name. Embrace Conway's law in your architecture, and don't subdivide within a service.