Я захотел, поэтому сделал
> Many domains see repeated patterns that are difficult or impossible to express as a library. Macros can allow those patterns to be expressed in a more concise and less error prone way.
> It is possible to demonstrate potential language extensions using macros. For example, macros would have enabled the with statement and yield from expression to have been trialed.
> By implementing new features as AST transformations, the existing compiler can generate the bytecode for a feature without having to modify the interpreter. A stable interpreter is necessary if we are to improve the performance and portability of the CPython VM.
и вообще они начали с того что датасатанисты используют питон и им нужны domain-specific расширения (а может и ненужны, поэтому давайте впилим макросы пусть сами пишут)