Can someone explain why companies use Cisco Secure Email Encryption Service (Cisco RES)

I'm trying to wrap my head around this from a security perspective... I have to explain to users that it is not okay to open an unsolicited encrypted.xlsm attachment one day... then the next day I have to tell them that downloading and opening "securedoc.html" in a web browser is perfectly fine.

The problem that RES is trying to solve, I think, is that emails are not encrypted in transit as they move through intermediary networks and mail exchanges. However, …

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