We usher people to their seats, yes. For example in cinemas or at weddings. Ushers and usherettes usher! We also use it figuratively as in.. the birdsong ushered in the coming spring... or the new political climate ushered in a new era.... so it is used in many situations where 'show in' or 'announce' might otherwise be used.

You can usher someone to his seat, such as in a movie theatre or stadium.