In this post to his site Marc Morera responds to some comments from another post about bundles dependencies in Symfony-based applications.

This post tries to answer the Magnus Nordlander’s blog post, and to explain why the Symfony Bundle Dependencies is not just a personal project to fulfill my bundles dependencies, but a practice we should implement in all our Symfony bundles as well.

Believe me, I had a big post to explain why people really need this bundle, but I think that you don’t need these words, but a simple and real example.

He points out a more "real world" example of why this kind of dependency system can be useful in Symfony development. He points out a common service (security.encoder_factory) that's used widely across many bundles, but also defined as a dependency in each. If the bundle dependency structure/tool was in wide use, this dependency would be define elsewhere and not as a part of the bundle itself.