Um... what? No. I mean, sure I can always take a screenshot, but my mail is mine. Don’t want people to share what you said, then don’t say it.
Maybe I do not get it. When is this going to be a good idea for a company to use? They aren’t going to use it on a coupon because if it really is a one time use they would just make the coupon only work once. If it’s for a rather unfriendly message it will only fuel the fire when the recipient sees it can’t be shared. I get that there are some documents a recipient might not want to share, but that should be their call and not the business.
What the heck is the point of confidential mode and such when you can just screenshot the E-mail?
I'd really rather companies not give people a false sense of security for sending sensitive information. If you can read it, you can save it. This is like Snapchat for E-mail, and everyone knows Snapchat isn't secure either, despite being a lot more proprietary and only accessible through an app.
Nobody ever promised total and unsurpassable security.
This is meant to protect against inadvertent or careless mistakes. Where both the sender and recipient know and agree the email shouldn't be saved, printed, or forwarded, but the recipient might forget or make a mistake, and he/she needs a simple barrier put up to prevent saving, forwarding, or printing. In addition to the above lawyer example, another example is planning a surprise party for a friend. You don't want anyone to accidentally forward that email, and everyone is on board; so nobody is going to be thinking of ways around it with screenshots.