It is my opinion that wedding rehearsals can play a big part in making the Bride more relaxed as she approaches the biggest day of her life.
Firstly, they can be fun! Walking down with your music playing in front of your friends in a relaxed environment.
Secondly, you will know where you are going to stand on the day and how things will happen.
and lastly, if you can have your rehearsal at the same time as your wedding, you will know approximately where the sun is going to be, this will help you to work with your professional photographer on the wedding day.
It is your choice to have a rehearsal, so if you and your celebrant have time, I would recommend you have one!