Interesting, I didn't know there is such thing on Li! Is this done by past employers?
From an attacker standpoint, if an attacker gains access to any email address with @example.com, they could pretend to be the CEO of example.com even if they compromised the lowest level employee.
Apple / Google developer program uses Dun&Bradstreet to verify company and developer identities. That's another way. But LinkedIn doesn't have that feature (yet).
Bad idea.
I never had my work e-mail address on LinkedIn, but then I made the mistake of doing this, and LinkedIn sold my work e-mail address to several dozen companies that are still spamming me a year later.