Did the user have a competing project? Never seen this before with much less interesting tech demos.

No, just someone who cares about the quality of HN's front page. The idea that waiting lists don't come with enough information to support a substantive discussion is pretty well established on HN.

What's the interesting demo here? Did I miss something?

The homepage video with multiple examples was a good demo, but maybe most people don't click that far. That would have probably been a better post.