IQ tests do have a purpose, primarily for streaming students in schools. Obviously schools need different classes for children/youths of differing abilities, and IQ tests are a good pointer for that.
I can even see some sense in having a club for people with High IQs, as it must get very frustrating for them trying to communicate with simple folk like you and I who simply can't keep up with their mental processes.
I'm not suggesting we all have our IQ scores tattooed on our foreheads. That's just silly.