They were writing the following about the Reverso dials (originally in French, Google translated):
Even during the Roaring Twenties, it was necessary to be animated by a manifest nonconformity to add a dial of color. Very few people chose brown or blue. As for those who chose red, they showed an exaggerated dandyism, thus affirming their pioneering character, their sense of elegance perfectly assumed but spiced with casualness and freedom. Because red catches the eye. Unquestionably. Located at the end of the spectrum of colors, it concentrates a powerful symbolic charge, incarnating in turn life, blood, desire, power, danger, love or fire.