Maybe they're "learning" how to use AI [1], but in at least some cases they're not learning what they're supposed to be learning from the class they're enrolled in [2]. The point of the assignments was never to produce the the answers as fast as possible by any means necessary [3], but to build strong foundations so that you can later do much more challenging/useful things.
If your assignment is "program X in assembly," and you just copy/paste the prompt into ChatGPT, you aren't learning assembly, you aren't learning important concepts relevant for low-level performance optimization, etc. etc. That was the point, not to produce X.
What would be useful is specific classes with assignments that are designed to be worked on with the assistance of AI. "AI-enabled SWE" etc. Lessons on how to effectively utilize it for research and learning. But those things aren't replacing learning the fundamentals, and probably can't unless AGI is achieved and actual knowledge is just economically irrelevant.
[1]: For a lot of undergrad assignments you can probably just copy/paste the description into ChatGPT, which I don't think qualifies as being difficult enough to merit "learning" how to do).
[2]: I guess this is "fine" if you're in the "AI will imminently replace all white-collar work" camp, but then its just dumb to be enrolled in college in the first place, unless maybe you're going for free.
[3]: In some sense, fully outsourcing your thinking to AI is the same as just paying someone to do your homework, which has always been possible but less accessible.