The point I was trying to make is that they are a pain when you are learning Angular. If you are lucky, you get understandable error messages if you don’t add the components and services where they belong. At least this is how it used to be as I remember. I agree that when you learn them, you can use them in useful ways but it’s another hurdle when you are just beginning.

And it is much easier now with the provicedIn for services and the CLI that automatically adds components to the module.