Passing Progression

I would say most teams' passing progressions go from deep routes to shallow routes. Some do use short to deep progressions. 

I had a question about long to short pass progressions. Wouldn't it make sense to make the progression short to deep? If you had a short route in the direction of the sideline (ie flat route of swing route), wouldn't you run the risk of that route getting too close to the sideline?

I realize that most teams use progressions that are deep to short reads, so it must have merit. Any thoughts would be greatly appreciated (pros and cons of each)