You can still use pure html forms wherever you want.
Zend_Forms try to help to easily implement the best pratices particularly validating, filtering and escaping user input. If you use pure HTML, you may forget these best pratices.
Question
It is mandatory to use a Zend Form everytime I need one? Can I do it with a simple html form in my phtml?
Are there dangers or trouble using the html one?
Solution
You can still use pure html forms wherever you want.
Zend_Forms try to help to easily implement the best pratices particularly validating, filtering and escaping user input. If you use pure HTML, you may forget these best pratices.