Interesting article. You link asyn I/O to performance and fault-tolerance, which is fine.

At the same time I think async I/O is an important factor to be able to maximize the use of computational resources. I mean, allows concurrency which itself allows a better use of resources. Or even more simply, with async I/O we can reduce the waste of CPU cycles spent just waiting for I/O operations to complete. This concept is discussed in some details here https://hackernoon.com/microservices-deserve-modern-programming-platforms-java-may-not-be-the-best-option-1v5z3tai.