Anthropic switched to HTML artifacts instead of Markdown because it speeds up...

https://www.mikegingerich.com/blog/anthropic-adopts-html-over-markdown-for-workflows/

Anthropic switched to HTML artifacts instead of Markdown because it speeds up their workflows and improves clarity. With HTML, they cut output errors down to just $0.08 per document and handle 4.4 million views monthly without breaking formatting