It sounds like a great idea. Even though the article is entirely correct in that Kaggle competitions are only a small part of machine learning, they are still

It sounds like a great idea. Even though the article is entirely correct in that Kaggle competitions are only a small part of machine learning, they are still a good way to learn some aspects. Even the data-cleaning that the author claims is missing from Kaggle competitions, is not really missing, it's just Kaggle have made your data cleaning much simpler. The main advice I would give is to find a problem where you can get an understanding of the data, i.e. not just treat it like a black box.