Movie bundles have a movie I already have...

Titling this is tricking, so I'm going to leave the title ending in periods.

There are a few movie bundles that have peaked my interest, however they have one or two movies in them that I already own.

How does this work? Suppose I bought the bundle, does said movie get added to my library twice? Is it worth buying 10 movies, and already owning one beforehand... and paying $20?