I love Black Eyed Lucies, infact I prefer them over Blues. But I believe it's because Black Eyed Lucies are a "Dead End" combo. Basically after you've made a Black Eyed Lucy you would only be able to breed that animal to other snakes as a Super. Now this may not seem like a bad thing but if you bred a Firefly to a Firefly and got a BLKEL then there is no way you would know if that animal is a Pastel BLKEL or even a Super Pastel BLKEL without breeding it out, which requires time, money, and most importantly: patience.

I personally have no issue with that but I'm sure there are people that see that as more trouble than it's worth.