This is looking really good, the ui and ease of creating forms is superb. WordPress has needed something like this for a long time.
The only thing that would make this (absolutely) perfect is being able to store the data within the WordPress database. What would be ideal is that when creating a form, if it was possible to create a new custom post type that defined the stored data.
Email is a good option, and being able to send the data to other resources is great, but it breaks the data out of the WordPress "system". For instance, create a form that stored feedback, rather than sending the data to a person through email, especially if there's more than one person working on the system, breaks the process of using a backend system in the first place. Being able to centralize the data and allowing a user to determine if it can be made visible or hidden really creates some powerful cms options.