Notice that pixel-doubling scaling preserves the image contrast and every other property, at the cost of not utilizing the additional resolution in any way. Things look the same despite you have double the pixels!
Interpolation filters produce errors when encountering high-frequency content of the image. These errors follow from ignored gamma correction (= scaled images tend to be too dark at high-frequency features) and modeling of image as infinitesimal points of specific color and intensity at particular points of a grid, rather than interpreting the image as an area-averaged sampling of an unknown light function. If you had a theory of the light function whose gridded area-average produced the current image, you would be able to resample such function to any resolution, and likely the results would be more natural too. In any case the upshot of the latter effect is reduction of contrast of high-frequency images. I studied the problem slightly here: