Making an exhibition film allows you to have a permanent exhibition.
Have you ever noticed that on the days of the exhibition, a small percentage of the audience visits your booth?
Also, after a few short days of the exhibition, the costs of building the booth and other costs you have paid will disappear.
Imaging and documenting the presence of that collection in the exhibition is practically a permanent exhibition for you, and the audience who have not been able to visit for any reason, will notice your presence in that exhibition by watching an exhibition film.
Making an exhibition film is far less than the cost of building a booth and other costs of attending an exhibition.