It is not flawed, it works quite well. My 5 year old was having a hard time till I took the cranks and training wheels off her bike for a couple of weeks. When I put the pedals back on she was a pro. Another common way to teach kids to ride a bike is to send them down a grassy hill. The learn much easier without having to worry about pedaling and getting hurt. (the same obstacles that are overcome on a bike without pedals)

Training wheels FTL.