When the WAS says that you should date, I think it helps to relieve some of their guilt feelings.
You should date only if you are done. Dating to make your W jealous as a means to get her to change is not the path you should take.
I started dating before my D was final when I decided I was done wanting my marriage to be saved. My wife had said early on following the bomb that she wanted me to date. She tried to ask for a second chance right before the D was final and tried to make me feel guilty that I was dating someone. So, from my perspective, she may have said one thing, but in the end it was not what she really wanted.