These have been tested and... surprise(!), never perform better than placebo.
The best than can be said about them is that at least they aren't actively damaging unless they stop the afflicted you seeking 'conventional'(?) treatment.
Technically, the best that can be said is that like any placebo, they can work pretty darned well. Parents use placebo treatments with kids all the time because they work. :)
A fair point, but then you might as well just administer a simpler placebo without the woo :). In the case of homeopathy that would be asking people to just drink a little water.
Anyway... IIRC the current consensus is that the "more extreme" the intervention appears the more beneficial the placebo effect is, so...
These have been tested and... surprise(!), never perform better than placebo.
The best than can be said about them is that at least they aren't actively damaging unless they stop the afflicted you seeking 'conventional'(?) treatment.