Here is one.

Let us grant a couple premises. First the belief that a cookie consent banner that provides a large button to accept and a multiple-click, read the policy first on another page opt-out process, complies with a law that says opt out has to be just as easy to opt in. Second, that your developers are more likely to use such a banner if they believe it's legal than if they knew they were doing something illegal. Third, that you are going to use the tracking information gathered via dark patterns implying consent by default not to sell to data brokers, but to actually better target marketing of your own publication. Fourth, that reading your epistemology journal will actually make the readers you target better at epistemology.

I think I might have discovered an epistemically useful false belief?

This isn't an indefensible stance or anything. While I have personally found some knowledge and awareness of cognitive biases to be pretty useful in tuning my own belief formation processes, I get those aren't the same thing as fallacies, though surely in the family. On the other hand, all the way from actually being a philosophy student 24 years ago to just spending more time than is healthy reading stuff like this on the web today, I think I've seen fallacies trotted out as a blunt object that ends discussions and indicts not obviously wrong reasoning more often than not.

But not at all universally. Especially post hoc ergo propter hoc. That is especially pernicious because it works as well as it does in terms of how humans come to build world models from experience. It works quite well when you want to know what happens when you punch a wall. Great for babies.

But it is not at all great for evaluating medical treatment. Saying it shouldn't be trotted out if we don't have randomized clinical trials indicating the opposite is ignoring that understanding of the fact that correlation doesn't equal causation is the very reason we have randomized clinical trials in the first place. Placebo effect, regression to the mean, and good old fashioned positive thinking if an ailment is largely subjective, are very real. A whole lot of treatments appear to work that can be proven to do nothing when they're actually put to the test. If using an unproven treatment doesn't obviously harm you and seems to work and you want to personally continue using it on that basis, feel free, but if you're going to trot that out as meaningful evidence that it actually works, pulling out post hoc ergo propter hoc is 1000% appropriate. Letting that slide is the basis of entire billion dollar industries that either do nothing but drain money or outright con people. Awareness of how causation can truly be demonstrated in complex systems that are not amenable to simply observing sequences of events and inferring what happened under the hood is a good thing.