I don't understand in this day and age why slide film would even be on anyone's radar. Unless you are projecting it, (or using it for some alt-process) slide film is nowhere near as versatile as neg film. Anyone who has done much scanning will know that neg film is a joy to scan compared to slide film. I could never understand why the publishing industry used slide film...
Good points. My view too.
Part of the problem to me was the lack of technical knowledge of the commercial photographers, on contrast and density ranges through-out the whole process from taking to final print-shop print.
Also I think photographers or ad firms had a better chance to sell a photo to a client if a halide transparency was presented on the light-table than than a halide print.
Finally printers had less to argue about hues if they got a transparency than a masked negative.
I think this all were the reasons for the slide being generally regarded the better source within commercial photographers.