Sure, everything "in real life" is more complicated. I think Kaggle to data science is as programming contests to Software Engineering. Will you say that doing

Sure, everything "in real life" is more complicated. I think Kaggle to data science is as programming contests to Software Engineering. Will you say that doing programming challenges is "unnatural"? Is it useless or bad? Because you may also argue that you never have to solve problems for speed, you rarely see clearly-defined problems, you rarely get to apply complicated or rare algorithms in real life situation. The thing is Kaggle helps developing certain skills. It doesn't mean it helps you developing all necessary skills for your "real life". Your real life and your job may require unique combination of skills and the only way to fully prepare for it is to actually do real project that are specific to your job.