DO WE REALLY NEED A CREDIT CARD?

Last year, I got a call from someone from a financial company (I never heard it before) who offer me a credit card. I wonder how they get my number and how they know my name? No privacy anymore in this world people! The girl just told me that they, her company, has special offer for me if I want to get a credit card from them. For a moment, I just thought Do I really need it? A rectangular piece of plastic, graphite, or metallic alloy that identifies a financial account. No, no, I didn't need it yet.