To add more realism to raids. When you kill someone irl it isn't announced to the entire world... at least until it makes the news. But that's the point.
Either don't get caught or do what you need to do before the server finds out.
Makes everything more... mysterious
An old but gold idea. No more death messages, allowing for stealthy murder and making active communication between town members necessary. Killing someone isn't always a "slain by" or "shot by" message. Sometimes it's pushing someone to their death, or breaking a block underneath them so they fall into a cactus farm, or what have you. Hence my proposal to get rid of all death messages, not just the direct murder ones. And, of course, it adds a note a realism which could add more depth to our ongoing server history.