Agreed, most paintings cannot be digitized properly, at least not in the way that would deliver the same experience that you get in a museum. I'm thinking of certain oil paints where the brush strokes are laid down thick, with multiple layers and the paint forms somewhat of a cup or caldera at the end of the stroke. Digitizing would necessitate capturing all of the colors, as well as three-dimensional scanning to see the textures from various angles. Then there's the way the painting shines depending on the positioning of the painting, the lighting, and the viewer. Capturing all of those variables would probably be terabytes of information and would require complex equipment for capture and some sort of VR system for playback.