What's the purpose of Justfiles?

Hello guys hope the question is appropriate to the sub after all Just is written in rust and I see it a lot in rust repos on Github. So my question is basically the title I am really curious why Justfiles got a lot of traction I did my due delegance and read the README of the project and it markets it self as a command runner not a build system(fair enough not trying to compete with Make) so why would I use Justfiles over let's say a shell script or custom cargo commands using (cargo-alias or cargo-make). So if you use Just what value does it bring to the table from your opinion? the only benefit I see is that apparently if you have a Justfile for your project it could act as a cross-platform script maybe?