doc: improve AsyncLocalStorage introduction

doc/api/async_hooks.md

@@ -973,6 +973,21 @@ chains. It allows storing data throughout the lifetime of a web request
 or any other asynchronous duration. It is similar to thread-local storage
 in other languages.
 
+## Difference with raw Async Hooks
+
+`AsyncLocalStorage` doesn't provide any new functionality that raw Async Hooks
+doesn't already provide: anything implemented with `AsyncLocalStorage` can be
+implemented with Async Hooks instead.
+
+The goal of `AsyncLocalStorage` is to provide a more performant and memory safe
+way to share state accross asynchronous calls. For example, the
+`AsyncLocalStorage` implementation doesn't involve any `destroy` callback,
+which considerably improves performance, and, in some cases, `destoy` can not
+be called or called very late which usually leads to memory leak in
+implementations using it.
+
+## Example
+
 The following example uses `AsyncLocalStorage` to build a simple logger
 that assigns IDs to incoming HTTP requests and includes them in messages
 logged within each request.