It's easy (even a bit fun) to grade and give feedback for good students. Meanwhile it's a huge pain to do for the weak students. You need to first figure out what they heck they're trying to do before you can tell them how to fix it, which may take a lot. I suspect code reviews for professionals is much more like the good student category.

If you're asking the students to define unique projects themselves, you run into new problems as students dig up the most obscure blogs they can find on the internet to download and give you. It's a never-ending adversarial struggle.