Encapsulating context interactions

The docs for the context API have this example:

import { getContext, setContext } from 'svelte';let userKey = Symbol('user');export function setUserContext(user: User) {  setContext(userKey, user);}export function getUserContext(): User {  return getContext(userKey) as User;}

I suppose that the code above would live outside a component, e.g., into a svelte.js file.

Then I would import setUserContext in some component (say <ComponentA>) so that the context becomes available to that component and its whole subtree.

Then a child of <ComponentA> can import getUserContext to access the context.

Now, my question is: why does setUserContext take an argument?

Can I define it like this instead?

export function setUserContext() {  setContext(userKey, user);}

So that I don't need to have the user in <ComponentA> just to be able to call setUserContext.

Also, bonus question, if the context was reactive (e.g., declared with a $state rune) nothing would change right?