Genderbend fanfic has a decent level of popularity. There are many fans who are interested in seeing how their favorite characters would be like if their genders were different. It has a following especially among those who enjoy exploring different interpretations of established stories and characters.
The unique aspect is the character transformation. When the genders are reversed, it completely changes the way we perceive the characters. For example, a male character who was known for his brute strength in the original may become a more subtly powerful female character in the genderbend version.