What you are describing is one of the main use cases at ESR Labs (where Josh was created): For developers it is very convenient to work in a single tree. For reviewers and CI it is useful to look at the changes in a larger context. For consumers/integrators however it is useful to only look at parts of the code that have to be shipped to particular customers, as submodules(or the like) in their repos. Plus a lot of package managers assume library == repo as a default, so it is also easy to integrate with those while keeping monorepo processes for development.