The whole idea of async functions is to run tasks concurrently and with simple syntax on a single thread. Hiding the actual concurrency under the runtime, only when it is waiting for IO.

It doesn’t matter that node is single threaded, nor does the GIL have any impact on single thread.

It’s once you start doing cpu heavy work inside the tasks this will hit you.

No, the single-thread aspect is just a limitation of Python & Node. Rust's Tokio is an example of a multithreaded async framework.

That's what happens when you write a blog about a technical topic you don't know much of anything about I guess

GIL is not a problem for concurrency. It is a problem for parallelism when doing CPU bound work.