Why, indeed! Particularly when you've been asked over and over again by 'experts' not to use the awful, cheesy lines on women? Well, let's tell you why. They have the potential to be very amusing. They can even be offensive at times, but they do work, depending on the circumstances. It's the equivalent of chumming with sharks. You'll get some positive answers if you put out enough there.
The key is to make your cheesy pickup lines exclusive. If the girl has already heard it, it isn't very meaningful. The only thing you want is a joke and a foot in the door to open a conversation. It's all for self-assurance. Your odds are slim if you put the line out and slink backward or if you act completely serious. Here are a couple of awful flirting catchphrases she could not have seen coming.
"You better be Jamaican, for Jamaican me crazy."
"What are your favorite breakfast foods? You're looking for me. I can smell it."
"A chubby penguin. [Wait, what?] I was just looking for something to say to crack the ice."