It is like asking why do people like sonic characters (sexually) people liking 日本动漫 characters, 迪士尼 characters etc. beyond your imagination. So your 问题 is not hard to figure out, 或者 anything. It's just a simple answer; because they think she's hot. There that simple.
Here is why 1) People think she is just hot, but i would rather say she is beautiful 2) She is very powerful monster and she might have been very 流行的 because she is the student of Dark Magician 3) she has a good ability 4) She is actually a good friend of Atem in ancient times