In my experience people complain about it because they are coming from a blocking first mindset. They're trying to shoehorn async calls into an inherently synchronous structure.

A while back I just started leaning in. I write a lot of Python at work, and anytime I have to use a library that's relies on asyncio, I just write the entire damn app as an asynchronous one. Makes function coloring a non-issue. If I'm in a situation where the two have to coexist, the async runtime gets its own thread and communication back and forth is handled at specific boundaries.

> Makes function coloring a non-issue.

Yes, having to rewrite literally all of your code because you need to use an async function somewhere is an issue.

An even bigger issue is that now you have two (incompatible!) versions of literally every library dependency.