It is not useless. Besides the point that the whole idea of science is that all of it is or could be useful in some way. This research establishes a platform on which you could build more specific research on that might be helpful in determining whether something is a personality trait, a sexual trait, or some kind of disorder.
Or if you want to go even more specific, maybe research like this could be used to convince governments that deny transsexuality that it in fact is possible to scientifically show that a person aligns more with a different sex, which might give them access to subsidy or insurance for surgery. Some people might be helped just because the science acknowledges the reality of their feelings.
In any case, your anti intellectual disposition is shameful.
Or if you want to go even more specific, maybe research like this could be used to convince governments that deny transsexuality that it in fact is possible to scientifically show that a person aligns more with a different sex, which might give them access to subsidy or insurance for surgery. Some people might be helped just because the science acknowledges the reality of their feelings.
In any case, your anti intellectual disposition is shameful.