People are focusing on the 26% being a low catch rate. But this is deliberate in order to lower the number of false positives on human work.

The big debate is in academia and most students will not risk ruining their degree to cheat this way. A 1in4 chance is huge when there are multiple papers that go towards your degree. It just isn't worth the risk.

Per the article. The 26% is the chance an AI piece is labeled "very likely AI". So they can catch out over 1 in 4 pieces generated by AI. The majority of AI writing doesn't get caught, but this also means the vast majority (>99%) of non-AI work doesn't get labeled AI.

In the context of academic work. Universities are at very little risk of accusing a non-cheater of cheating. The 1in4 catch rate while low is a huge deterrent for potential cheaters. If I knew that I had a 1/4 chance of getting caught and punished, I would not cheat. Especially as i had to submit dozens of papers as part of my degree.