Notice the different perspectives in the image above, for lenses of differing focal lengths, caused by the distance between the camera and subject having to be changed - to keep the ratio of subject size to image size similar in each example.
Cropping a wide angle image to a longer equivalent will not remove this effect.
Moving closer, with a wider lens, will introduce more of this effect.
Cropping will also not affect the DoF in the image - where changing the lens and shooting position probably would have.
The original image (which is not mine) can be found here.