I tweeted this recently, and it deserves a little more explanation (and permanence):
This is Bad Design™. It will lull users into a false sense of control and result in painful mistakes. If someone can see your message on their screen, they can share it. https://t.co/qmXBoiYqAB
— Travis Northcutt (@tnorthcutt) April 15, 2018
The key quote:
We’ve now learned Google will also introduce “Confidential Mode,” which lets Gmail users stop recipients from forwarding certain emails, or restricts the ability to copy, download, or print them.
Here’s the thing: if you send someone an email – even if it “expires” after a set amount of time, or gmail somehow prevents them from copying/downloading/printing text and/or images from it, they can still share it. All they have to do is take a screenshot – or a literal picture with, say, their phone – and share that.
Sure, this has some utility. For instance, you could share a password with someone with an “expiring” email, and be sure (not that I’d trust Google to actually delete anything…) it won’t be sitting in their email inbox forever, just waiting for a future hacker to come along and find it.
But promoting this as a way to prevent sharing of information is misleading, user-hostile, and bad design. Period, full stop.