[diarrhea]

I understand async/await in Python to be entirely single-threaded. So is, for example, C#'s implementation: https://learn.microsoft.com/en-us/dotnet/csharp/programming-... ("The async and await keywords don't cause additional threads to be created.")

[tomnipotent]

Eliminates blocking on IO requests, letting the event loop spend CPU cycles doing non-IO work. Alternative is CPU doing nothing while waiting on IO, which for something like a web app doing lots of small network requests to database/cache can add up to a lot. CPU work is still single-threaded.