Anthropic switched to HTML artifacts from Markdown to speed up internal work...

https://wiki-triod.win/index.php/How_do_I_add_interactive_UI_elements_to_an_HTML_artifact_without_making_it_huge%3F

Anthropic switched to HTML artifacts from Markdown to speed up internal work like planning, code reviews, and reports. HTML cuts output costs to just $0.08 per file and loads content 5x faster, which boosts productivity