Rebecca,

Each CI framework has different syntax, capabilities, and requirements.  The PyTools environment attempts to generalize the edk2/uefi aspects of the setup, build, and test but regardless there are things that should be done as "steps" in the CI framework being targeted.  This is why there is a split between PlatformBuild.py and the azurepipelines files.   PlatformBuild.py and the ReadMe.md files all have details about how to run locally as well so those aspects can be tested independently from the CI framework.

thanks
Sean