Other than the help with a job hunt, it has so much to do with having professionals/teachers with years of real-life experiences around, IMHO.
It's like, for instance, learning how to swim. Many people can learn some basics of swimming on their own, simply by spending time in water. They can learn how to use their arms and legs efficiently or how to stay on the surface of water with a minimum effort. But, there are quite a few details which are almost impossible to learn on your own before many years pass or without having a professional teacher - such as the importance of exhaling under water, body roll etc.
I don't know programming counterparts of this instances, but I guess there are so much more important details than there are in swimming.
If you can do this why do you need a bootcamp? Genuine question. For help with the job hunt?