Alexandra Daddario should've played the main role

They had beautiful and sexy Alexandra Daddario in the cast, but chose Elisabeth Moss (who IS NOT good looking at all) as the SUPPOSEDLY PRETTY girl? I don't get it.
Acting abilities were not an issue since this movie doesn't need any, so what was the reason?
The opening scene with Alexandra is the only moment from this dull movie I will remember tomorrow, and I'm sure many viewers have the same experience, so the director, the producers and everyone involved should've known better which girl should play the main part.