This isn't a thing, which makes me think you're arguing in bad faith.
Clients load images asynchronously, and no personal email is sent with a logo and catchphrase header. I've never seen that in my entire life and I've been using email with a lot of people, for a long time.
Formatting is an issue however, and the addition of formatting to email can be useful and add to the conversation.
To take the hn example again, the text portion of your comment is broken on mobile because hn doesn't support proper formatting. This has made your comment harder to read.
Clients load images asynchronously, and no personal email is sent with a logo and catchphrase header. I've never seen that in my entire life and I've been using email with a lot of people, for a long time.
Formatting is an issue however, and the addition of formatting to email can be useful and add to the conversation.
To take the hn example again, the text portion of your comment is broken on mobile because hn doesn't support proper formatting. This has made your comment harder to read.