The possibilities are endless. Humor can accomplish so many wonderful things beyond getting you laid. Here’re just two examples.
Very often you need to use joking as a means to avoid answering her questions.
If she asks whether you are single, you can say:
“No. I’m dating a girl now… (Staring at her) Apparently she’s not aware of it.”
You can use humor to ease the tension if you get into quarrels with women. But make sure you don’t sound sarcastic. There are various techniques to use, based mostly on logic and rhetoric.