Someone posted further up that when you send a "secure" email to an outside the company email address, they get a link to ope the email and have to enter a one-time code that is emailed to them.
So even forwarding is broken, as is search for those of us that search our emails a lot.
This is a Gsuite admin feature, leaving personal Gmail does nothing and if you happen to control your Gsuite account... just don't turn it on.