I didn't move close to my job to spend 30+ minutes a day commuting.
I don't want to show up sweaty to the office.
I can run errands or meet someone for lunch. After work I wouldn't need to go home to get my car if I, on a whim, wanted to go across town for whatever reason.
Bay area is popular for biking because they make it difficult to park. Where I live they make it easy with large free parking lots. I'm in a large coastal city.