Just to add another piece of feedback - I'm someone who has written production Clojure + Datomic apps and still don't understand what this product actually does. Not withstanding the direct link to the demo, your actual homepage (http://www.hyperfiddle.net/ - had to work too hard to find it) doesn't say much about what this does.

The first paragraph of actual text on the page says "Isn't a tool this powerful too dangerous for production?" - you're trying to debate a problem I haven't even mentally flagged because I have no idea what it does. The demo vid is way too fast (and long - the worst combination) for me to get an understanding. I'm generally in-favor of having a demo video as the first thing on your site but only if it's max 20 seconds long and gives me a very clear picture of what it does.