my guess (and vague recollection from 40 years ago..) is that every high end bike had the same Campy components, frame tubing, etc. One of the few ways to make a bike stand out was to add some bling!
'fer instance.. my 1982 Olmo Competition. It has pantographed cranks, chainrings, shifters, brake calipers and levers, seatpost and stem.
The cranks were special too. Campy Record cranks with the Mexico treatment, where the arms are profiled and the spider arms have the flutes slotted.
Does it make a functional difference? Only if you count how your friends spend time looking at all of that cool pantographing!
the whole bike...
the cranks and chainrings
shift levers
brake calipers
brake levers, with some extra holes too...
stem
seatpost
the fork crown also had the Olmo logo cast into it, which is fun too....
so, pantographing was a great way to make a bike stand out and to really put the brand logo on display!
Steve in Peoria