Not particularly useful when this is on the debug menu
The seed is already display in the game's F5 debug menu. I would have liked some kind of extra on top of this, maybe an algorithm to try to reverse the seed hashing that's applied when you start the world with a string seed. I can almost see a use case if the chat command were locked behind the server priv and the server software was modded to lie about/omit the seed info that gets sent to clients. Still, not particularly useful as it is.
Edit: Apparently some games/mods can hide the debug menu with HUD flags. This is useful for those cases, I suppose.