Reactjs: Are there advantages to using React components over normal functions?

Question

Taking for example this sample from the React.js docs

var Avatar = React.createClass({
  render: function() {
    return (
      <div>
        <ProfilePic username={this.props.username} />
        <ProfileLink username={this.props.username} />
      </div>
    );
  }
});

var ProfilePic = React.createClass({
  render: function() {
    return (
      <img src={'http://graph.facebook.com/' + this.props.username + '/picture'} />
    );
  }
});

var ProfileLink = React.createClass({
  render: function() {
    return (
      <a href={'http://www.facebook.com/' + this.props.username}>
        {this.props.username}
      </a>
    );
  }
});

React.render(
  <Avatar username="pwh" />,
  document.getElementById('example')
);

For cases like this, with components with no state, and if I'm not going to use jsx: are there any disadvantages (performance or otherwise) to just using functions instead of creating components? IE, reducing it to something like this (written in ES6)

var { a, div, img } = React.DOM;

var Avatar = (username) =>
    div({}, ProfilePic(username), ProfileLink(username));

var ProfilePic = (username) => 
    img({src: `http://graph.facebook.com/${username}/picture`});

var ProfileLink = (username) =>
    a({href: `http://www.facebook.com/${username}`}, username);

React.render(Avatar(username), document.getElementById('example'))

Answer 1

If you are not using JSX, and do not need any of the run-time features of the core classes (like componentDidMount, etc), then there is no advantage to creating the classes unnecessarily, and in fact, it will be (slightly) more efficient overall.

By creating concrete (yet very simple) wrapper functions such as you've done with Avatar, it improves code readability. However, if you ever do start using JSX, you'll need to switch to createClass so that properties are properly passed (since the initial properties are not passed to the constructor function as they are in your code).