NSA will start to deposit the cash you send, its just "Metadata"
email guarantees none of those traits 1. Encryption from server to server is optional, 2. Who knows how many MXs are hit until it finally makes it to my mailserver 3. Mailservers have know authentication mechanisms that ensure someone cannot send mail on my behalf.
Yes, well configured mail servers will make attempts at these things through SSL/TLS connections, doing direct connections only (no proxies/relays) and by only accepting mail from servers listed as MX servers or with SPF records etc.
Thanks for the -4pts.