If you compare resampled and 1:1 sections, you'll see that on resampled image the noise level is lower.
By today's consumer digital cameras different ISO settings are available but this still hasn't a lot advantages comparing to classic film photography. Really, at higher ISO level, more closed aperture or shorter shutter time could be used for night or lowlight exposures but the noise of the picture increases a lot. When images are resampled to smaller dimension, the noise is less visible.
This clipping shows how the noise becomes visible when the sensitivity is set to ISO 800. Section data:
Original image data: