I disagree. A real project will teach you a set of problems that are useful at most day jobs but these coding challenges will help you learn a class of skills and techniques that are very hard to learn/figure out on your own. These are much more centered around Computer Science problems than typical software craftsmanship problems. You need both (CS and software craftsmanship based skills) if you want to a complete well rounded Engineer.
I have 11 years in the industry in various jobs. I was very good in the algorithms and data structures part of my course when I studied it, but the frequency that I actually get to use any of that stuff is maybe a couple of weeks per year.
I would say that learning libraries and how to use them will be far more use, as most common problems have been solved, implemented, put in a library and tested for you. A good programmer will use that library rather than reinvent the wheel.
