The main issue is that sync functions can't call async functions, but in Python, you can bypass that restriction with asyncio.run.
4) Red functions are more painful to call
I guess for me if I reach back to my memory my real problem with asyncio was that it used decorators and wrapping my head around how it was a crazy abuse of generators, completely broke my internal model of how python works (and also how at the time debugging became problematic), and maybe not so much the ergonomics, so strictly speaking a different set of ergonomic problems than in the colored function article