Why does babel-preset-react-app use entry instead of usage in useBuiltIns config?

[Chorer]

From the babel-preset-react-app config:

(isEnvProduction || isEnvDevelopment) && [
  // Latest stable ECMAScript features
  require('@babel/preset-env').default,
  {
    // Allow importing core-js in entrypoint and use browserlist to select polyfills
    useBuiltIns: 'entry',
    // Set the corejs version we are using to avoid warnings in console
    corejs: 3,
    // Exclude transforms that make all code slower
    exclude: ['transform-typeof-symbol'],
  },
],

Using useBuiltIns: 'usage' can import necessary polyfill only and make bundle size smaller. Why babel-preset-react-app still choose using entry instead of usage?