Or the illusion thereof. I'm not sure about that. I'm afraid I don't have access to the numbers any more, but I've seen firsthand how HTML emails can result in

Or the illusion thereof. I'm not sure about that. I'm afraid I don't have access to the numbers any more, but I've seen firsthand how HTML emails can result in more engagement with customers – more likely to follow links, in particular. HTML mail is more likely to go into the Junk mailbox. Is that really true? If anything, I've seen that regular customers—assuming you are not a tech-focused business—are less likely to read emails in plain-text formats! On the other hand, IDK what "useful features" of HTML you talk about, other than being (relatively, possibly, and never certainly) pretty. I don't think that 'pretty' is really fair – more like 'can have visual design'. If it were the case, surely magazines and newspapers would be nothing but plain text too, as would all mail we receive. In contrast, I would be a bit freaked out to receive something like a utility bill in the mail that was in plain text, without a company logo, or formatting, or other elements that make it more usable and identifiable. I do completely understand that you prefer plain-text email, and so do I. But I'm pretty sure we are in the minority there, and that most people treat email in the same way as they'd treat physical mail – and that probably means that the relatively invisible downsides (tracking, size, poor formatting etc.) are outweighed by being formatted more effectively.