What is the difference between tasks?

Question

gulp.js

Is there any particular difference between:

function js () {
  return src('src/js/*.js')
  .pipe(babel())
  .pipe(dest('build/js/'))
}
exports.default = parallel(js)
exports.js = js

and between:

function js () {
  return src('src/js/*.js')
  .pipe(babel())
  .pipe(dest('build/js/'))
}
gulp.task('js', js)