[NoraCodes]

Ah. I think the difference is that when I send emails, I do so to communicate information, rather than to elicit people to buy a product.

[franga2000]

Even when communicating important information, using the company design has been the norm since graphic printing was invented. Even something as transactional as a bank statement or court summon will use the sending organization's logo, fonts and colors.

[yakshaving_jgt]

Are you relying on the user's email client to convert plaintext URIs into interactive hyperlinks in transactional mail?

[NoraCodes]

No. As I said, I'm not advocating for plain text only emails, just simple ones.