[Taywee]

Yes, there are other ways to do it, but adding another tool as an option is good, too. Being able to nest containers makes composeability a little bit better, too. For instance, if I want an image that effectively has multiple base images, instead, I can just run both base images in containers inside of the parent container. You can bundle a lot of related containers into an arbitrary app container. It's a natural expression of programming composition into a containerization context, in my opinion.

Containers being nestable components makes a lot of natural wants much more natural to express.