This is a misunderstanding of placebo. Placebos do not cure anything. They change the user's subjective observations. For example, they're effective for pain because pain is subjective.
The placebo effect has been demonstrated many times to actually be able to alter objective bio markers and lab test results. This is why it’s so critical to do placebo controlled studies of drugs to determine that they actually have efficacy beyond the placebo effect.
Having said this, the placebo effect is no justification for medical deception. When people want medicine they shouldn’t get sold placebos that are marketed as actual medicine.
> A placebo presented as a stimulant may trigger an effect on heart rhythm and blood pressure, but when administered as a depressant, the opposite effect.
If placebos have been experimentally observed to induce changes in their subjects, then it holds that placebos can be used to alleviate symptoms similarly to conventional medications.
Comparing things to placebos does not imply that placebos have no effect. In some cases, placebos have very powerful effects, which is why we compare against them.
Having said this, the placebo effect is no justification for medical deception. When people want medicine they shouldn’t get sold placebos that are marketed as actual medicine.