The line isn’t nearly as crisp as you make it sound.
For example, is a nurse’s uniform as “rationally justifiable” as a hazmat suit? No. But it does serve a useful purpose for nurses, in that it frequently makes patients more likely to treat them as authority figures.
Now, you might ask why patients do that, but in some sense that doesn’t matter. Even if patients are irrational to do that, it is still pragmatically useful for nurses to wear the uniform if it reliably obtains that benefit.
But in fact it isn’t a senseless thing for patients to do, either, in that wearing a nurse’s uniform is a more costly signal if I’m not a nurse than simply saying “I’m a nurse” (since other nurses might see me wearing the uniform and punish me), and therefore more reliable than simply saying that.
More generally: uniforms are one way humans signal a certain kind of social status, and status signaling is a valuable function.
The line isn’t nearly as crisp as you make it sound.
For example, is a nurse’s uniform as “rationally justifiable” as a hazmat suit? No. But it does serve a useful purpose for nurses, in that it frequently makes patients more likely to treat them as authority figures.
Now, you might ask why patients do that, but in some sense that doesn’t matter. Even if patients are irrational to do that, it is still pragmatically useful for nurses to wear the uniform if it reliably obtains that benefit.
But in fact it isn’t a senseless thing for patients to do, either, in that wearing a nurse’s uniform is a more costly signal if I’m not a nurse than simply saying “I’m a nurse” (since other nurses might see me wearing the uniform and punish me), and therefore more reliable than simply saying that.
More generally: uniforms are one way humans signal a certain kind of social status, and status signaling is a valuable function.