One here! Il Divo (the 4c's actual concept car sold at Villa D'Este for the Preferitti) had them so zero issues with "Lamborghini doors" (ugh FYI, Alfa Romeo invented the gullwing on the 33 Stradale, so pretentious? The Stradale had 220hp and can't hit 200mph on a good wind so... Education. Knowledge is a precious thing to waste on hipshot opinions)...
So I did buy 650s dihedral door hinges because apart from a custom adapter plate that will bolt in the stock locations, they are nearly perfect (3.5-4mm extra from door needed). I am waiting on the quote for the custom door work, as the tensile/"tounge"/"flexion" (loosely translating the Italian tech terms) specs on our tubs meet having a complete door weight up to 90lbs, so how they "beam" from the bolting mounts dont matter, put that idea to death because the tub can do it, laughing. But: the doors weigh too close so I also have to decide how to lose some weight there (Scara73's carbon doors are a fast/one-stop way to getting that done, but I don't want to lose my motorized glass and side airbags, so not that simple) so the redesign can last, rattles-free, like an OEM execution.
As for "it doesn't need them"... I daily mine, am 6' and weigh a skinny 170lbs, do stretches/pseudo-yoga and some martial arts every morning , and if you can get out of the damn car when the only space is between two fat ass trucks, or parallel to a 45mph street, dihedral doors... Man, even swan doors, make a world of difference.
I have spoken with a few AR ppl and they did consider vertical doors in the beginning, but cost QUICKLY nixxed it. No problems there as we would be owning 2015+ 8c's had they went "full retard", spending at least $300k+. I just wish the doors, however the opened, took some of the side sill where your foot goes with it, like a Mclaren.