Why does React.createElement need to be called twice?

I am in the process of learning React and was stuck at once place. To make things clear, I am first trying to use React without any JSX. All I am loading is the React and React DOM library. I defined a component like this:

function Weekday(props) {
            return React.createElement('p', null, `Today is ${props.day}`);
        }

        let dayElem = React.createElement(Weekday, {day: 'Monday'});

        ReactDOM.createRoot(document.getElementById('app')).render(dayElem);

My question is why do I need to call createElement twice? The function Weekday is already returning a React element. So, what did I have to call createElement another time while passing it the function name Wednesday. Why couldn’t dayElem simply be like this:

let dayElem = Weekday({day: 'Monday'});