I\'ve read the manual many times, I\'ve scoured the posts offered by Google on the subject, I have even bought a couple of books that deal with ZF. Now, why am I still confused?
whycantitbemorethan25c mentioned them above, but ViewScripts give you extremely fine-grained control for rendering forms. Zend_Form is meant to be fast and so it assumes many defaults like standard decorators and orders the element the way they were added to the form object. With the ViewScript you can skip much of that that and place all of your elements however you would like within normal HTML.
Don't skip over the concept of Decorators entirely though. They style the individual elements even if they are used in a ViewScript later. For example, you can use them for error messages as others have suggested.
If you have very complicated form that has multiple data points with similar actions (think of a list of users with active/inactive buttons and a delete button for each) you should consider Zend_Form_SubForm. The subforms can utilize the ViewScripts just like normal forms and if you cascade a form with a ViewScript with subforms with their own ViewScripts you end up with nicely contained logic and presentation that is much more powerful than just a straight form.