They certainly have flaws, but I have to disagree that student course evaluations are “counterproductive.” It’s sad that some professors give higher grades to get higher ratings in return, and even sadder that some students will go out of their way to take easy classes (because of the wide range of difficulty, college GPAs are as much a measure of course selection as of work quality) — but my college had evaluations, and I often found them quite valuable.
Students comment, for example, on lecturing ability, fairness in grading, reasonableness of workload (I don’t think it’s wrong to avoid professors who intentionally assign more reading than can plausibly take place, just to test your ability to “find the important parts”), usefulness of reading assignments, political indoctrination, etc. And while it’s absurd to put a professor’s learning on the same level as that of his students, I do think student suggestions can improve teaching.
In short, it gives students a reference with which they can make the most of the few spaces in their schedules. Also, yes, when the instructor arbitrarily gives you Cs on all your assignments, with little comment, and isn’t much help when you ask about it, it’s fun to give a scathing review (not that that ever happened to me).
Finally, if the school doesn’t create and oversee these systems, they pop up unauthorized elsewhere on the Internet, anyway.