Ah, but we rarely know when something is a placebo, and if we do, it doesn't work anymore.
Let's say you have two treatments, they both work for you and they both cost the same thing, except one is an active medication with side effects and one is a placebo, with no side effects, you just don't know it, which is why it works.
Which would you prefer? And which is worth more?
Think about it, the answer isn't obvious, or, it shouldn't be.
In this case I would advocate for a third option, that is in my opinion the best way: finding out how the placebo effect helps and work out how to replicate it without either medication or placebo.
Here is a simple example. I know a couple of people who take some placebo medication if they bumped into stuff because they believe they will be getting less hematomas. If they realized that a small superficial hematoma isn't a bad thing at all, they wouldn't need the placebo in the first place, saving themselves the money, the worry and a good minute going to the fridge to get the placebo pill. This would even work if they had a medication that actually worked.
Other placebo effects might be more difficult to get though because they might be more complex to figure out or more difficult for people to comprehend or to execute. Examples could include that people relax in anticipation of relief and that that helps with the symptoms. In this case relaxation exercises could work.
I'm not totally against using the placebo effect, but I don't think it's the optimal way.
Also, just to add: Placebos can produce placebo side effects too.