When a well informed patient asks for a treatment that they would like to try and hears "there's no evidence" it usually means;
a) I haven't looked at the evidence
b) I don't agree with the evidence
c) The treatment costs too much
Even just a couple of years ago my health board (Lothian) were putting out written material claiming that there was "no evidence" for micronised progesterone being safer and more metabolically favourable than synthetic progestins.
Funnily enough this changed when it went off patent and became cheap, without the emergence of any new clinical evidence.
I don't think the formal research will ever be done in regard to the non-libido benefits of testosterone because having sex with men is seen as far more important than female patients' health and quality of life, and also because patient-centered outcomes are subjective in nature, therefore collecting such data would involve women being listened to and believed.
The genie is also so far out of the bottle that we all know what we need to say to get testosterone, so neither the main indication for treatment nor the outcome are actually being recorded, which will really hamper observational studies, and nobody with significant symptoms of hypoandrogenism is going to volunteer for a randomised controlled trial where they could get the placebo.