Quote Originally Posted by Deke
Because movies are made for theaters, not your living room. When someone is making a movie they don't think "hey I should make this formatted perfectly so some couch potato can watch it on his plasma." They think, "I want to make this look as badass as I possibly can so everyone rushes to the theater and critics love it." Just about any film that values it's cinematography (think Dark Knight, Gladiator, LOTR) is going to want it to look as grand and "epic" as possible. This is achieved by shooting in very high aspect ratio.
Thank you.