The point is that "having a role" is not a core part of their model. You can also tell them to have a style, or tell them to avoid certain language, or not tell them anything specific but just speak in a way that makes them adopt a certain tone for the responses, etc.

This is similar to how you can ask me to roleplay as a wizard, and I will probably do it, but it's not a requirement for interacting with me. Conversely, an actor or an improviser on a stage would fit your original description better: they are someone who you give a role to, and they act out that role. The role is a core part of that, not an incidental option like it is for an LLM.

That's right. But I'm not sure how that is supposed to lead on from the point I made above.

It's not a requirement for interacting with them, but if you want them to behave a certain way then it's helpful to ask them to behave that way.

It's not necessary to ask a human to behave like a clown but if you want them to behave like one, say for the clown movie you're shooting, then helps to ask them to.

It's not necessary to ask an LLM a question, but if you want an answer then helps to ask one... Etc etc.

Maybe I'm missing your point but it seems a bit absurd, could you clarify?