I also prefer plain text, but in most of my emails I talk about technical stuff, or I send transactional emails that require actions, in which case showing buttons is a much better user experience than plain text.
You could have a larger text instead of a button, but changing font size is also HTML and not plain-text anymore.
Those templates should account for all types of people and accessibility levels (including things like ADHD, where you need a big red button to click, otherwise you get overwhelmed by a block of text).
I don't think so. I certainly didn't have to resort to HTML to make that link readable and clickable.
Easy. Don't.
That's the great bit. You don't have to.
A lot of alerts, reporting, quotes, code snippets, short documentation or step by step instructions, etc.
I don't just send emails to say "Hey, let's meet at 5". You know the memes with "this could have been an email", it usually is this case.
Just to be clear, most of those rich emails are the automatic/transactional emails.
I didn't mean to be sarcastic but it's just that to me, philosophically, email is a plaintext technology that had HTML bolted on to it kicking and screaming, and it's always been kind of crap. People like me hate things that are fundamentally ugly and crap even if they are useful. The web was designed for HTML from the start.
Human language is an unnecessary abstraction, just like images.
I wish everyone would communicate in pure Binary.