You can't think of a reason why I would want to do this because you have no idea of my particular circumstance.
Customers only have to enter their name, phone number, and order information into the form because we contact them to confirm the order by phone. We never contact by email because we don't sell any products online.
These are orders from residents in our own city so there is never any need to know their email. If I cant confirm an order with a real person on the phone the order gets scrapped. This is a unique service and I have no time to explain.
Of course it would be stupid if the site was selling products online but its not and never will. There will never be any need for a customers email address as I only confirm orders over the phone.
So don't assume that you know what other people need or want. Most people obviously need it or they wouldn't be asking for it.
Think about it. Removing the email input field from the contact form of an online shop would be the same as committing business suicide.