Thanks for the suggestion, it is very interesting to compare appearance of interpolated/non-interpolated image when voxel size is approximately the same as the pixel size on the display. I created a video of a continuous zoom from smaller voxels than display pixels to much larger voxels than display pixels (and zoomed in the video 4x so that it is easier to see differences):
If image is not interpolated then there are waves running over the image as you zoom in (or pan), depending on which voxels are skipped when voxel size is similar to display pixel size. If image is interpolated then zoom is continuous, smooth. Without the 4x zoom, the waves are barely visible on a modern high-resolution screen, so in everyday usage these artifacts are not that distracting.
At the very end there is a very clearly recognizable C-shaped dark structure in the interpolated image, but it is barely visible in the non-interpolated image, probably because our eyes do not average voxel intensities very well. For me, this image demonstrates very well why we need to use interpolation for image display.
