If you hand an electronics engineer an amplifier, she can take it apart and tell you what it is capable of doing, without reading the manual or seeing an ad for it.
If you show a civil engineer the plans for a bridge, he can figure out how heavy a truck could drive over it, regardless of what the sign says.
Too often, we resort to hand waving and random hopes for the things we build, merely asserting that our hocus and our pocus will have an effect. But the artifact we leave behind might do little or nothing without the fancy packaging.
There’s nothing wrong with the cognitive dissonance that placebos cause. It’s effective indeed. But it works even better if there are actually active ingredients in the potion we’ve created.