Everybody knows about Webform so why would we want another survey system in Drupal? Entityforms takes a very different approach by using an entity and standard fields approach to forms. Entityform submissions are field-able entities.
Imagine never having to click around your website after a site update, worrying that something may have broken. Imagine never getting a call from a client after a site update, telling you that something in fact has broken.
I have been coming up against the same Drupal 7 requirement over and over recently - the need to have a form in a block with a separate template file I can pass over to the front-end guy to weave his magic.