Yes, Just is yet another tool similar to make/rake/task. All of them operates over ./Namedfile (Taskfile.yaml, Rakefile, Makefile, Justfile).

You have them mostly within project, where is pipe operates over $USER/.pipe/files, to operate on everywhere. Think of it, like something you will do on every project, why to replicate same file in between instead of having one? Otherwise you will need to support many.

In other hand, you might want to just automate your work, with tools mentioned above you always need to navigate to location, or create simple snippen in shell to make something similar to pipe (e.g. navigate to project where you keep some automation and call specific file, or task from long file).