Education is one of the most important investments in life (followed closely by investing in relationships). Many people around the world spend a fortune on a good school for their kids. Sadly, this fortune is often wasted and they end up blaming their children for not making the most out of the opportunity they were given. It is similar to investing in the share market or in property, you find a lousy house or buy very shaky shares and complain when they do not increase in value.
Children spend the majority of their most valuable childhood years in educational institutions. Think about it this way: out of 7 days a week, 5 of them are dedicated to schooling. If the kids are also stimulated in other ways, they may even spend some of their weekends in educational endeavors.
Much like other investments, the decision whether to invest or not, and in what to invest depends on the potential return. If the return is high, it is considered a good investment. If the return is low, it is not a very good investment, and if there is likely to be a loss, it is a terrible investment.