why do we have default components in react-native code example

Example 1: export default react

import React from 'react'; // get the React object from the react module

class HelloWorld extends React.Component {
  render() {
    return <p>Hello, world!</p>;
  }
}

export default HelloWorld; // expose the HelloWorld component to other modules

Example 2: export default class react

import Template from './components/templates'