The "dandy" theme is usually invoked in order to promote the image of bygone elegance, flawless grooming and an exquisite toilette (fashion sense), and the 1920s was still interested in these fashion icons. George Brummell was known for his clean linen, bathing and shaving rituals (to the point of obsession), whilst Comte d'Orsay was known for his use of perfumes, even to the point of taking perfumed baths. The D'Orsay line decided to use the image of Comte d'Orsay to promote its fragrances in 1908. (The tale of his being a parfumeur is all marketing, however. See "The Perfume Handbook," second edition.)
I understand Varon Dandy has been around since the 1920s, but can't say I have used it or sampled it.