That’s the reason we have to still use fax machines right?
I know there are ways to do encryption like PGP on your message directly or I think email sent over TLS? But that isn’t the default right and that’s why I can’t send a picture of my license to the insurance company directly over email?
Zip files aren’t very secure by default, however you can specify better encryption with better zipping tools. It would be more accurate to say you should put the content into an encrypted archive file.