Closures are handy for a number of things. Many event listeners are closures

    const [username, setUsername] = useState('')
    const onChange = event => setUsername(event.target.value)
    const onSave = () => dispatch(saveUsername(username))
    return (
      <div>
        <input value={username} onChange={onChange} />
        <button onClick={onSave}>Save</button>
      </div>
    )
       

This code contains two closures