Previously, people were superstitious, if anyone undertook to put on a suit or dress of death, it was only for the sake of performing a magical ritual or a theatrical performance. Modern people are less susceptible to superstition, and someone does not believe in the existence of the spiritual world at all (which does not absolve from responsibility), so people are not afraid to dress up in costumes and dresses that resemble death.
One of the first designers to play with death was Elsa Schiapareli, she created one of the first death dresses. The idea for the design belonged to Salvador Dali.
This was in 1938, then such dresses could only be worn at the carnival, and today, for some, death's outfits are acceptable for everyday wear. For example, Gothic girls will happily wear such a dress.