For me it's about training, but also stress reduction and freedom. In a city like LA or Seattle going anywhere is all about parking and traffic. On most days it is faster and way less stressful to get around the city by bike. It ruins my day if I have to drive to work or to the gym. Our second car is a beater Jetta, and I have 3 bikes that I maintain so the saving money argument might be a bit tenuous. But if I only drive that car once a week it will certainly last a lot longer which will save me money in the long run.