Erniang is way more popular than her ranking in the 108 Stars of Destiny.
This is of course in part because she is one of the only 3 108 Stars of Destiny women. But her story about making human mantou is particularly fun!
She's also quite seductive, which gives directors a good opportunity for a bit of fan service. See e.g. kknews.cc/history/6epp2pp.html for a still from The Water Margin showing some good cleavage for example.