Is it possible to remove the extra arrow function here?

Hi!
The tutorial has an example like this:

class Square extends React.Component {
  render() {
    return (
      <button
        className="square"
        onClick={() => this.props.onClick()}
      >
        {this.props.value}
      </button>
    );
  }
}

This component used in the Board component like this:

renderSquare(i) {
    return (
      <Square
        value={this.state.squares[i]}
        onClick={() => this.handleClick(i)}
      />
    );
  }

We have closed the context in a function that we pass to onClick in the Board component.
But why don't we just pass this.props.onClick to onClick in the Square component? Why are we using closures here if we already have the right context inside?

I wrote like this: (link to codepen)

class Square extends React.Component {
  render() {
    return (
      <button
        className="square"
        onClick={this.props.onClick}
      >
        {this.props.value}
      </button>
    );
  }
}

This works successfully

It is clear that the variant from the tutorial will also work. But further it says:

When we modified the Square to be a function component, we also changed onClick={() => this.props.onClick()} to a shorter onClick={props.onClick} (note the lack of parentheses on both sides).

So my variation only works in a functional component? But above it also worked in class components. I think this might confuse some people.

首先阅读关于提升 state 和函数组件的教程链接章节，然后比较两个 onClick 示例及其附带的说明。检查类组件示例是否需要澄清传递 callback 与调用 callback 之间的区别。当教程清楚地解释两种形式为何都能工作，以及较短的形式适用于何时，即视为完成。