Probably you're right, but it's a convention used by me and others to signal "that's it folks" and cue applause, or raspberries and rotten tomatoes, as the case may be. It also lets the audience know what the song's called, as that's not always obvious from the lyrics.

As I said, I only do it by a sort of convention at the end of an unaccompanied song, never an accompanied one, where I usually have an obvious finish in the musical accompaniment.