Anything that makes email development easier is great I guess, but have personally found MJML great for solving the issues you'd run into, and not sure I want yet another abstraction layer on top of that which makes it more limited...
It still uses MJML for the actual templates, but it is a translation layer between markdown and the template itself.
If you need to author a lot of emails with LLM this does seem like it would be a great fit.
That's assuming the crawlers haven't ingested it all already...