In many ways, pushups are a more "legitimate" chest exercise. Benching requires technique and momentum and involves elbow/tendon strength, whereas pushups are pure pectoralis major and minor. A lot of guys can bench heavy but can't do 20 pushups. Since the pes are usually an easy bodypart to develop, pushups make a great pec workout, leaving them flat, wide and hard. Meanwhile, guys who fall in love with benching often wind up with bulbous, bunchy chests.