Because Please can build many languages already (and you can easily write rules to teach it about others) you always invoke one tool to build any language or run any test, simplifying your continuous integration and development processes.

Continuous integration & pre-merge testing.

We've developed Please in tandem with our internal integration tools, so whenever any of our engineers merges a pull request, we invoke it to make sure any affected tests are passing before merging it in. Because Please allows fine-grained dependencies and knows them for every test, we can run just the affected ones to keep this step fast & lightweight.