You don't send an
email to an IP address. You send it to an account on a server.
Also, with IPv6, a LAN has a gazillion addresses (2^64
or 18.4 billion, billion).
And the server writes your home IP into the received headers. At
least some servers do.
Yep, but you didn't use my address to send the email. It was sent
to your SMTP server, then forwarded to my ISP's server, where my
email client found it.