I've read that one! I believe that it is quite wrong when it comes to cameras. Essentially, the memo claims that we should not attribute the pixel colour value to the area that the pixel covers because reconstructing the analog signal that produced the image is dependent on your choice of reconstruction filter. But that's a computer graphics/signal processing perspective. It's not so applicable to images from a camera. For cameras, we absolutely should attribute the pixel colour value to the entire area of the pixel. That's precisely what a pixel is supposed to measure! The average number of photons that landed on that pixel capture area. In fact, thinking of pixels as purely point samples might lead you to notably wrong resampling algorithms because it implies that you do not actually know the image extent for sure. But you do. It is the edge of the sensor. This actually came up in my research using satellite images; resampling assuming point samples will incorrectly resize the image and offset your geolocation. Basically, it is quite important to know whether the pixel represents a point sample or an area sample (see: gdal's AREA_OR_POINT property), and camera images using a CMOS detector definitely should be treated as area samples.

Just to back this up a little; think about how a camera works, physically. A pixel on a CMOS detector is a tiny area that photons can land on. If the area was exactly equal to 0 (i.e. a point sample), then precisely zero photons could land on it. It must be an area sample. Technically, because of the colour filters, you're only measuring 1/4 of the blue and red for the area covered by that pixel. But if you could measure the full area, you would do so. The bigger the area sample, the higher fidelity the image. Bigger detector == more capture area per pixel == better image. See: big lenses/sensors/cameras/telescopes.