To be fair, HN is also an Opinion Network, so the same logic could be applied. People love to discuss things, and without experimentation with different formats

To be fair, HN is also an Opinion Network, so the same logic could be applied. People love to discuss things, and without experimentation with different formats, we would all still be using usenet (or sitting around a dinner table, which would arguably be better). This was a personal project of a friend of mine though, hacked together in 5 days to learn Rails. So I believe it was less about "What problem is this solving?", and more "What would be a cool thing to build?".