Everyone has their own favourite Sailor Moon character but it's almost never Chibi Usa but when you really dive into it, she never really gets any out right hate and that might because of her darker older form of Black Lady.

Black Lady was created when Wiseman preyed on Chibi Usa's negative emotions caused by a time space rift transforming her into the dark form of Black Lady, serving as a major antagonist for the Black Moon Arc;
The result was an effective villain who took out Tuxedo Mask and proved to be the best villain for Sailor Moon and her friends until the summoning of Neo Queen Serenity set her free along with Sailor Pluto's help.
Three reasons why this saves Chibi Usa as a character.
1. It gives more weight to her original introduction back in Sailor Moon R removing much of her tagalong kid status.
2. It would later give inspiration to another infamous Sailor Moon villain, Mistress 9.
3. It more than makes up for her god awful arc in the SuperS seasons.
But also for a bonus fourth reason, evil is just way sexier and both Black Lady and Mistress 9 personify that well and feel right at home during the early hot topic goth era.
But the biggest take away from Black Lady's appearance was that Sailor Moon was growing up, stakes were higher, more adult themes were being explored and it gave the series a much grander appeal than it had originally with it's first seasons.
Mistress 9 will follow this post, but her creation didn't quite have the same effect on Saturn.