With the Quick Reply button, only email addresses from the user's Facebook account can be collected, so it's not proactive and flexible.
How can a user actively enter the email address they desire.?
If a webview form is used, the user will not receive an automated email sequence
There is two option for collecting email described here https://www.youtube.com/watch?v=GnRaKx0CWHA
Bot quick reply & also with postback button which load as webview.