[JamesSwift]

It is a powerful abstraction that ends up being a replacement for several kinds of tools depending on your use case.

It can be a way to declaratively configure a system similar to ansible.

It can be a way to isolate runtimes (e.g. ruby v2.8 and ruby v3.0) in different projects similar to rbenv / virtualenv.

It can be a way to define an application in a self-contained way so that the target platform needn't have needed software installed beforehand similar to docker.

It can be a way to install packages/software to your system in a well-defined way similar to many package managers.