WebPush PushSubscription vs messaging.getToken?

Good day. I implement on the site a subscription for push notifications. I can not figure out what the difference between the two approaches.

The first is to simply get the token and send it to the server, then send messages by accessing it

function subscribe() {
  // запрашиваем разрешение на получение уведомлений
  messaging.requestPermission()
    .then(function () {
      // получаем ID устройства
      messaging.getToken()
        .then(function (currentToken) {
          console.log(currentToken);

          if (currentToken) {
            sendTokenToServer(currentToken);
          } else {
            console.warn('Не удалось получить токен.');
            setTokenSentToServer(false);
          }
        })
        .catch(function (err) {
          console.warn('При получении токена произошла ошибка.', err);
          setTokenSentToServer(false);
        });
    })
    .catch(function (err) {
      console.warn('Не удалось получить разрешение на показ уведомлений.', err);
    });
}

The second is to get the object PushSubscription and use what he returned to send messages

function subscribeUserToPush() {
  return navigator.serviceWorker.register('service-worker.js')
  .then(function(registration) {
    var subscribeOptions = {
      userVisibleOnly: true,
      applicationServerKey: btoa(
        'BEl62iUYgUivxIkv69yViEuiBIa-Ib9-SkvMeAtA3LFgDzkrxZJjSgSnfckjBJuBkr3qBUYIHBQFLXYp5Nksh8U'
      )
    };

    return registration.pushManager.subscribe(subscribeOptions);
  })
  .then(function(pushSubscription) {
    console.log('PushSubscription: ', JSON.stringify(pushSubscription));
    return pushSubscription;
  });
}

{
  "endpoint": "https://domain.pushservice.com/some-id",
  "keys": {
    "p256dh":
"BIPUL12DLfytvTajnryr3PJdAgXS3HGMlLqndGcJGabyhHheJYlNGCeXl1dn18gSJ1WArAPIxr4gK0_dQds4yiI=",
    "auth":"FPssMOQPmLmXWmdSTdbKVw=="
  }
}