Doing well on Kaggle is basically a resume builder and probably would get you into jobs you wouldn't otherwise get. Not much different than topcoder in that sense. Some people can make a living just winning competitions.

You don't beat their model, just those of everyone else in the competition. A very different game.

You can't beat their model because they don't include all the data they use in the competition dataset. It's a highly sanitized and simplified toy problem used for hiring and marketing. They don't even tell you what the features are so it's impossible to use domain expertise to constrain the fitting problem (this is a critical component to building profitable trading models because of the signal to noise ratio in the data)