JM Tran, somehow I think you missed the whole point of Desmond's post ( did you read it or just look at the pictures? ) as it was purely about the relationship that
shutter speed plays when photographing with an ambient
light source that you want to balance or complement with flash output.
In the clear concise and detailed post, Desmond has presented facts and a very clearly illustrated examples, not just a quick patch up of how to make the image "better".
Yes your post has summarised some of the points and purely repeated others that Desmond took the time to post in detail to help people have a little more thorough understanding of the topic instead of a few lines that may not educate those that haven't had a great deal of experiencing flash use.