From normal product photography you wouldn't know this MB 300L model has functional gull-wing doors or liftable boot, but when you show the customer this animation, he instantly understands.
Your customer is now informed and, more importantly, interested.

Interactive manual is another possible usecase.
Renowned office chair maker RIM has made this manual, showing all possible adjustments for his chair.
Products presented this way give a lot of information to the customer and answer many of his questions.
Your customer now doesn't have to travel to a salesroom where you need a staff to present all the features, hope he doesn't forget anything!

Gmini, company well-known among parents, here demonstrated the folding ability of its baby carriage.
Did you know that some carriages can transform in few simple steps?
Why have two carriages, when you can have one - show that your product is simply better than others!