Experimentation is a toolkit for optimizing things. That's it. For example, if you are Uber, you might offer a bonus to people to work more. How much money do you offer? Is there a relationship between how much you pay and how well people perform? To determine this, you need empirical data, you need to be able to split people into groups, and you need to be able to measure things about the groups. And you need some guardrails to keep yourself from p-hacking. As the number of people and the amount of money increases, the number of interesting questions rises rapidly. These are all things you get from an experimentation platform.

Experimentation works best when a) it's easy to try different parameters for a thing, and b) there is a lot of money involved.

Your comment is weird to me because you seem to be implying that experimentation is a cult because there are no things worth optimizing, and/or optimizing things has a negative societal effect. Those things are obviously true some of the time, but it's not very interesting.