pyrDown, pyrUp vs resize (blur operations)

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What are pros and cons of pyrDown? What is quality and performance difference between pyrDown/pyrUp and resize? I have created this code to make tests. I am using 2557x3993 RGB image gained from scanner (the image contains mainly BW pixels, but few lines of small red text too).

#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
#include <iostream>

using namespace cv;

int main( int argc, char** argv )
{

  /// General instructions
  printf( "\n Zoom In-Out demo  \n " );
  printf( "------------------ \n" );
  printf( " * [+] -> Zoom in  \n" );
  printf( " * [-] -> Zoom out \n" );
  printf( " * [ESC] -> Close program \n \n" );

  char* window_name_1 = "Pyramids Demo";
  char* window_name_2 = "Resize Demo";

  cv::Mat src, dst_pyr, tmp_pyr;
  cv::Mat dst_resize, tmp_resize;

  /// Test image - Make sure it s divisible by 2^{n}
  src = cv::imread( "../../data/strana210.jpg" );
  if( !src.data )
    { printf(" No data! -- Exiting the program \n");
      return -1; }

  tmp_pyr = src;
  dst_pyr = tmp_pyr;

  dst_resize = src;
  tmp_resize = dst_resize;

  /// Create window
  cv::namedWindow( window_name_1, CV_WINDOW_AUTOSIZE );
  cv::imshow( window_name_1, dst_pyr );

  cv::namedWindow( window_name_2, CV_WINDOW_AUTOSIZE );
  cv::imshow( window_name_2, dst_pyr );

  double t1, t2;

  /// Loop
  while( true )
  {
    int c;
    c = cv::waitKey(10);

    if( (char)c == 27 )
      { break; }
    if( (char)c == '+' )
      { 
      t1 = (double)getTickCount();
      cv::pyrUp( tmp_pyr, dst_pyr, Size( tmp_pyr.cols*2, tmp_pyr.rows*2 ) );
      t1 = 1000*((double)getTickCount()-t1) / getTickFrequency() ;
      t2 = (double)getTickCount();
      cv::resize( tmp_resize, dst_resize, Size( tmp_resize.cols*2, tmp_resize.rows*2 ) );
      t2 = 1000*((double)getTickCount()-t2) / getTickFrequency() ;
      printf( "** Zoom In: Image x 2 \n" );
      std::cout << "pyrUp: " << t1 << "ms" << std::endl;
      std::cout << "resize up: " << t2 << "ms" << std::endl;
       std::cout << std::endl;
      }
    else if( (char)c == '-' )
     { 
       t1 = (double)getTickCount();
       cv::pyrDown( tmp_pyr, dst_pyr, Size( tmp_pyr.cols/2, tmp_pyr.rows/2 ) );
       t1 = 1000*((double)getTickCount()-t1) / getTickFrequency() ;
       t2 = (double)getTickCount();
       cv::resize( tmp_resize, dst_resize, Size( tmp_resize.cols/2, tmp_resize.rows/2 ) );
       t2 = 1000*((double)getTickCount()-t2) / getTickFrequency() ;

       printf( "** Zoom Out: Image / 2 \n" );
       std::cout << "pyrDown: " << t1 << "ms" << std::endl;
       std::cout << "resize down: " << t2 << "ms" << std::endl;
       std::cout << std::endl;
     }

    cv::imshow( window_name_1, dst_pyr );
    cv::imshow( window_name_2, dst_resize );
    tmp_pyr = dst_pyr;
    tmp_resize = dst_resize;
  }
  return 0;
}

Now I press "-" few times and here are the results:

Debug version:

** Zoom Out: Image / 2 pyrDown: 113.24ms resize down: 56.1988ms

** Zoom Out: Image / 2 pyrDown: 41.836ms resize down: 8.95756ms

** Zoom Out: Image / 2 pyrDown: 18.0705ms resize down: 12.6991ms

** Zoom Out: Image / 2 pyrDown: 4.68942ms resize down: 6.21811ms

** Zoom Out: Image / 2 pyrDown: 1.23563ms resize down: 1.62395ms

Release version:

** Zoom Out: Image / 2 pyrDown: 119.267ms resize down: 59.2019ms

** Zoom Out: Image / 2 pyrDown: 29.2641ms resize down: 8.74413ms

** Zoom Out: Image / 2 pyrDown: 18.1238ms resize down: 12.7287ms

** Zoom Out: Image / 2 pyrDown: 4.63131ms resize down: 6.25275ms

** Zoom Out: Image / 2 pyrDown: 1.2686ms resize down: 1.6301ms

Zoom In with Release version: ** Zoom In: Image x 2 pyrUp: 1.3809ms resize up: 2.2338ms

** Zoom In: Image x 2 pyrUp: 5.29369ms resize up: 5.08109ms

** Zoom In: Image ... (more)