3. Projection:
Slide projection is unsurpassed concerning resolution, sharpness, brillance and tonality. Digital projection cannot compete at all in this regard, because the resolution of digital projectors is extremely low. The imaging chain in digital projection is very weak, the sensor resolution is destroyed by the much much lower resolution of the digital projector. And all digital projectors have also the general design flaw that in vertical direction the resolution is even about 40% less than in horizontal direction.
And they are extremely expensive.
Slide projectors, even new ones, are very cheap in comparison.