I hear you. We have had a ton of adoption of our Chrome Extension, which also has features like Open Tracking, Send Later and Salesforce Integration. When you click to create a reminder in the extension, we do populate the "bcc" field with the text based version of the email just to show users how it works.
That said, I agree that a simple explanation on the homepage would be useful for people who are just interested in the reminder piece.
That said, I agree that a simple explanation on the homepage would be useful for people who are just interested in the reminder piece.