If this were the case, Tour de France cyclists, who spend the most time on their bikes, would have enormously cushioned seats. Padding, in actuality, deforms and increases contact, making longer rides less pleasant. However, padding does help to distribute your weight more evenly when sitting for long periods, which some cyclists find necessary to prevent muscle pain and other injuries. Cyclists use panniers because they are easy to carry. If you put lots of heavy things in one bag, it will be too heavy to lift up and down buses or trains. So you need many small bags instead. Each cyclist needs to decide how much space he or she is willing to give up by not carrying a full saddlebag. Also, because cycling is hard work. Even with a baguette under your arm and a bottle of wine in your jersey pocket, you're going to need all the help you can get if you want to finish that stage in first place.