Comment by mk12
Colors for 2 ways of doing IO vs colors for doing IO or not are so different that it’s confusing to call both of them “function coloring problem”. Only the former leads to having to duplicate everything (sync version and async version). If only the latter was a thing, no one would have coined the term and written the blog post.
IMO the problem was never about it actually doing IO or an async actions or whatever. It's about not being able to a call a async function from a sync function. Because in my experience you almost never wholesale move from sync to async everywhere. In fact I would consider that an extremely dangerous practice.