As with all services, it comes down to "engagement". If there's a single long post, people only argue under that post. But if your long idea is split into 10-

As with all services, it comes down to "engagement". If there's a single long post, people only argue under that post. But if your long idea is split into 10-20 tweets, you can have a different argument under every tweet, and every tweet under that can again have another thread of arguments. Resulting in: engagement. Twitter is not, and has never been, a platform for discussion. It's either for shouting your stuff into the universe or arguing.