My understanding is that the strip essentially encodes the credit card number, and that when you swipe it, you pass the number. Therefore, "stealing" the card i

My understanding is that the strip essentially encodes the credit card number, and that when you swipe it, you pass the number. Therefore, "stealing" the card is as easy as MITM-ing that (with a skimmer). The chip, on the other hand, answers a query that proves that it knows a secret. If the attacker listens to the exchange between the card and the reader, it doesn't learn the secret itself, and the next transaction will ask a different query.