>New comments and reactions update instantaneously

Killer feature - in that its going to kill the process.

This is chat. Or close enough to chat that its going to be used as chat.

Chat is terrible for comments. A flame war on chat escalates at the rate at which someone can hit enter.

like the wake of a ship, the comment area will expand, and defeat moderation ability to clean it up.

Flame wars are bad enough, flame wars on chat which persist like comments are a bad idea.

Make it update in non-real time.