The main reason for getting a film is it is truly the best way to relive what could someday be forgotten. The audio remembering what was said. The imagery captured through the lenses of professional high definition cameras. A film in all situations is a wonderful memento to pass down for generations.
This practice is not a good idea unless the friend or family member is an experienced professional. One reason is they lack more often than not the necessary equipment to do the job properly. Second reason is because they are a friend or family member in attendance and not a hired professional. Their focus will more than likely be to enjoy the event and not to capture all the important moments. Good rule to go by is one gets what one pays for.