Some aspects of mythology or alchemy are also useful, but that doesn’t mean it’s an overall respected science or isn’t caused by a secondary phenomenon. As that wiki states, it’s the suggestion aspect that is useful, not the hypnosis itself (the methodology) and there isn’t really a consensus on its efficacy.
The statement “If it’s useful for anything, then it’s not pseudoscience” is an example of a logical fallacy known as a false dichotomy or a false dilemma. This fallacy occurs when someone presents a situation as if there are only two mutually exclusive options or possibilities when, in fact, there are more potential alternatives or nuances to consider.
In this case, the statement implies that something can either be “useful” or “pseudoscience,” with no middle ground or other possibilities. In reality, an idea or concept can have some utility or practical applications while still being considered pseudoscientific or lacking scientific validity. The two categories are not necessarily mutually exclusive, and this oversimplified dichotomy ignores the complexity of the subject matter.
This is basically part of the joke that this headline implies.