I think a first answer could be answering with a question:

"Why do so many people use makefiles to just manage tasks/scripts/wrappers instead of using pure bash scripts"

One reason may be that they are already using make in their project for actual build targets, but I see many pure task-only makefiles out there, so its not the only reason.

I think another reason is ease of use - The syntax is very terse and you can get a useful task runner with just a few lines of text.

With regards to Run, one of the additional features it brings is the ability for your 'commands' to be any type of script and not just bash.

You could have small scripts coded ruby, python, perl, etc all mixed together and managed within a single Runfile.

Thanks for the question - I hope that helps - Please let me know if you have any further comments or questions.