jQuery gives you enough freedom while doing animations. There are methods like
Also in certain situations, you can
dequeue() animations where you introduce a delay before any event, and let a sequence of animations in progress.
So, there is no point is delaying animations by default, since in most cases it is not required, however can be used at any point in time.
Also, It is very much a case specific scenario.
For example, to make the user show that something happened when they performed an action on the page, say, while reloading visible data on the page, a delay is usually present, and then it is shown to make the user comfortable that something has changed on the page with their action.
However, animations on their , own take some time, which is usually mentioned in the code. So say, when a user takes his mouse over an event that triggers an animation, the result would take up (animation time + delay + time to load data).
One does not want to increase time (insert a delay) for an important action, say over a button which leads to a payment page, or a booking page.
So to sum it up, if there is a gap in which the user sees information that is crucial to him, and will make him stay on the page, there is no point in inserting a delay. In other scenarios, a delay is usually inserted, example, image sliders.