The problem is that the tool fails the fundamental rule of "should I use AI to solve this problem".
AI is safe to use *only* if you meet the following criteria:
1) The output doesn't matter (e.g. writing a story for your kids is safe)
2) Someone qualified assesses the veracity of the output prior to using its decision in a way that could cause harm.
The problem is this tool will *always* fail these two tests (so long as its false positive rate is > 0%).
There are virtually no ways to use the tool that are objectively assessable -- there are no experts who can verify its output without external information that invalidates the point of the tool -- and virtually every case for knowing if text is written by an AI is about making a judgement decision regarding the author where failing it is harmful
It's worse than existing plagiarism tools, which say "this text is probably plagiarized from [this other text]", because there you can go and look at the other text and see if there's context that's missing. Like, maybe you're "plagiarizing" a properly-attributed quote, or the author of the other text is also you.
But here it's just "expensive magic computer brain says this student is a fraud", and administrators are going to assume it's true, and have few ways to independently validate it
The power of AI is its ability to *enhance* humans to make decisions, process information, and automate time/mentally consuming but generally pretty low-stakes tasks (like drafting an email).
But when you step past that into delegating life-changing decisions to an AI, either explicitly (loan company says no) or implicitly (magic box says 12% yes and human operator develops rule of thumb to press "go" if number > 10), you're going to run into a world of Kafkaesque garbage really quickly.