There's something to be said about the benefits of having a serialization boundary between parts of the code that's a natural consequence of microservices, but

There's something to be said about the benefits of having a serialization boundary between parts of the code that's a natural consequence of microservices, but it's something that could be employed in a monolith just as well. Then if at any point you actually need to split out a module into its own process or machine, it would be trivial to do.