How are you defining a solid object with 'no wavelength'? Black would be the perceived colour, or lackthereof, of said object. The laser would see it the same a

How are you defining a solid object with 'no wavelength'? Black would be the perceived colour, or lackthereof, of said object. The laser would see it the same as any colour of cube though. The point is eyes are extracting more information from the image. Visible light interactions with the object exists in reality and capturing that information brings the image closer to reality, not further. It tells you more about the cubes properties. As an extreme example, you might have a space documentary start by showing an image with a few stars, saying "it seems quiet", then showing the same image with a bunch of colourful gasses visible, saying 'but the reality is beyond what our eyes can perceive, in infrared the image is full of detail'. Reality, actual reality and not our perception of it, is made up of every detail, the more of that information you can capture the closer to reality the image.