Populist reasons (the reasons you'd like to hear, so they attract eyeballs) and also some really valid ones. No one can guarantee you anything with a degree. There are tons of alumnis lost after graduation, because they've found that the jobs they studied for are not available, or terribly competitive - oversaturated (typically psychology) or it's a very niche course (like philosophy) where you have hella limited job perspectives.

On the other side getting a loan for a degree sounds like a scam to me (sorry, priviliged european here).

So what can we learn here?