Yep that's cuz we practice Evidence Based Medicine. If it works, it works, we don't care for the mechanism. Mechanism of action is only ever a hypothesis anyways.

But as a 2nd point, we don't always do things by evidence either. Obstetrics is an example of an entire field where there is not much evidence, and people practice what was passed down to them. The reason is because often you cannot do an RCT in an ethical way with Obs.

Additionally, often times when we prescribe a medication/treatment, there is a really significant chance it won't do anything for you. The number needed to treat before one person experiences a benefit could be quite high, like 10 or 15. We still do it if the benefit outweigh the risk.

TLDR: We don't care how it works just that it works. Some fields like obstetrics have little evidence for many things. And just cuz there is evidence, doesn't mean it'll help most of the ppl who get it.