Frankly, the inherent contradiction of your vehement support for something you think shouldn't exist has confounded me, and your position that video games, guns, and alcohol also should not exist is so far on the fringe of society that it's hard to take at face value.
I am not conflating "useful" and "good overall". You are the one claiming that something (let's pick TikTok) is useful to its users, but shouldn't exist. Why should something that is useful to its users not exist?
When you say useful in this case, I think you mean that users are deriving short term pleasure from interacting with the app by choice. You also seem to believe that the long term effects of near-constant social media consumption are so harmful that it should be banned. In my mind, if the latter is true, the short term pleasure is not in reality useful. If the latter is false, then the short term pleasure could be considered "useful" but there's no need for a ban.
This pattern also seems to hold with your example of students using chatGPT to avoid writing papers themselves. If I needed to succinctly describe the actions of someone who is spending tens of thousands of dollars a year and at least several hundred hours a year at a place for the express purpose of learning yet also actively avoids making effort to learn, "stupid" is a word that jumps to mind. Yet you seem to be arguing that is not the case because they know they're making a bad decision, which is hard to accept as an attempt at honest dialogue.
In both cases, people are trading long term gains for short term enjoyment. Calling that choice "stupid" may be rude or blunt, but it's not incorrect in most instances.
I'm not trying to put words into your mouth so I would welcome an actual answer to my question above (Why should something that is useful to its users not exist?), but I did want to explain what seems to me like an inherent contradiction in your position.
Yes, it is possible for something to be useful in specific circumstances but still be bad overall.
We have disagreements about what counts as useful. If our definition is "This is only useful if it leads to longterm happiness" that seems way too specific and would exclude too much.
It's stupid to cheat, I agree and try to make that clear. What I'm saying is the claim "Students think they're learning when they cheat using AI" assumes students are so stupid that they think cheating off of a robot will help them learn as much as writing an essay themselves. That's obviously wrong.
If so, that's a pretty radical position, and if not I don't understand how they're relevant.