[Step888]

It's an interesting idea, but it has a few drawbacks.

You can't defend yourself when you're dead. You can't be your own witness. Nor can you face your own accuser. Also, who would you trust to speak that truth for you?

Also, grieving family members are not the most rational people. Doing this could trigger violence in practice.

And obituaries have a legal function. As a modern society, we want to encourage the publication of obituaries as soon as someone passes away. It mitigates the risk of potential fraud.