Former journalist here. This structure is also known as "inverted pyramid"[0]. CIA has a book[1] that details the process to apply the structure recursively to build an article. Beware of the potential pitfalls of "stating the key first": 1. The key point might be complex and requires a build up – rushing to the point could confuse your readers; 2. What's "most important" depends on the reader and if you write for a…
Probably there is a good reason why people usually talk the way they do: build up a context, make the listener (or reader) familiar with what is going on and why we are talking about this. And then explain what we are actually talking about.
This inverted pyramid talking style is so artificial and makes me question whether the advocates of it are just using it as an excuse to not read or listen to anything. It makes people indeed just hurry through communication.