You can find some benefits and limitations of each kind of space organization below.

That said, I wish more people would talk both sides. Yes, every dependency has a cost. BUT the alternatives aren't cost free either. For all the ranting against micropackages, I'm not seeing a good pro/con discussion.

I don't think seeing it in Rails PRs naturally means we should do it blankly. Put it another way, what's the justification in those PRs for doing it?

If you don't understand both sides of an issue, you cannot make an intelligent choice; in fact, if you don't understand all the ramifications of your actions, you're not designing at all. You're stumbling in the dark.