Counterpoint: a monolith usually contains a complex init system which allows multiple ways of running the codebase. Microservices can avoid at least that one complexity.
You mean like profiles? Monolith can run like a front service or background worker depending on the config?
In a technical sense it is a complexity, but IME pales in comparison with the alternative of having to manage multiple services.
I actually really like this model, it's pretty flexible. You can still have specialized server instances dedicated for certain tasks, but you have one codebase. What's very sweet is that for local development, you just run a single application which (with all enabled profiles) can fulfill all the roles at the same time.