You are completely missing the point. Even on a bicycle with a simple drivetrain, there are dozens and dozens of things that could go wrong that would be fairly simple to fix in daylight but impossible to fix at night. Flats are only one thing...and random at that. You could have a bolt come loose, spokes break, brake pads slip, chain break, flats and many, many other things that can happen completely at random. You could even drop something...keys, glasses, wallet, gloves, etc...while doing something else that your generator light would be useless to help look for. Having a light that you can turn on and leave on is extremely helpful and comes in handy. At the very least, you should carry something that you can use as a back up in case something happens to your main light. Stuff happens.