Because it still works, but feel free to remove it completely or turn it into an Error.
If the game still works at that point, we should not throw an Exception. However, since your comment states that the else condition should never be reached, reaching it indicates some programming error, so it should log an error message, or at least a warning (devlog.error or devlog.warning). Creating ingame text for a condition that should never be reached seems like wasted effort.
It's no problem of course. I just want to suggest we do it differently in the future