Ngrx Effects with Nx

effects.ts

// Effect with no Nx added
loadBrokersBasic$ = createEffect(() =>
  this.actions$.pipe(
    ofType(BrokersActions.loadBrokers),
    switchMap(action => {
      return this.brokerApiService.getAllBrokers().pipe(
        map(brokers => BrokersActions.loadBrokersSuccess({ brokers: [] })),
        catchError(error => of(BrokersActions.loadBrokersFailure({ error })))
      );
    })
  )
);

// Effect with Nx pipeable operator fetch used
loadBrokersNoDataPersistence$ = createEffect(() =>
  this.actions$.pipe(
    ofType(BrokersActions.loadBrokers),
    fetch({
      run: action => {
        return this.brokerApiService
          .getAllBrokers()
          .pipe(
            map(brokers => BrokersActions.loadBrokersSuccess({ brokers: [] }))
          );
      },

      onError: (action, error) => {
        console.error('Error', error);
        return BrokersActions.loadBrokersFailure({ error });
      },
    })
  )
);

// Effect with Nx Data Persistence Module used
loadBrokersWithDataPersistence$ = createEffect(() =>
  this.dataPersistence.fetch(BrokersActions.loadBrokers, {
    run: (
      action: ReturnType<typeof BrokersActions.loadBrokers>,
      state: fromBrokers.BrokersPartialState
    ) => {
      return this.brokerApiService
        .getAllBrokers()
        .pipe(
          map(brokers => BrokersActions.loadBrokersSuccess({ brokers: [] }))
        );
    },

    onError: (
      action: ReturnType<typeof BrokersActions.loadBrokers>,
      error
    ) => {
      console.error('Error', error);
      return BrokersActions.loadBrokersFailure({ error });
    },
  })
);

1. Is it just for readability that we're using the pipeable operator instead of switchMap?
2. What does the DataPersistence module get us that the fetch operator doesn't?

Here's the source code for the DataPersistence module: https://github.com/nrwl/nx/blob/master/packages/angular/src/runtime/nx/data-persistence.ts