UITextFieldDelegate vs UITextField control events

Question

If I want to handle changes to a UITextField, such as the user typing in it; it seems like this can be done either by assigning a delegate to that text field, and then having the delegate implement shouldChangeCharactersInRange, or by adding a target to the textField, and handling the UIControlEventEditingChanged event.

Aside from the fact that with the delegate method, you can return NO and therefor stop the user from making the edit, is there any difference between these 2 things?

Same question for handling the beginning of editing or the ending of editing. It could be done either with the appropriate delegate methods or with the appropriate events. What is the textField delegate actually for if the control events can do the necessary work?