The answer is Faster and also easier. Longitudinal waves are waves which travel in the direction parallel to the medium, say for example a sound wave. When you scream in open air so that the ear or receiver from the other end can be reached by the sound it requires the air molecules to vibrate from left to right or right to left depending on the direction to propagate the sound wave generated when you scream. However say for example you use a string and cup to propagate the sound, you need not scream from the source for it to reach as you have the molecules from the string which is more compact than the molecules present in the air.