Historically if in the US if someone gets a hold of your card, if I report it as soon as I know there is a problem you are legally out $50, and the credit card company and merchant has to eat the rest of the loss. In most cases the credit card companies figure since they have to take the rest of the loss they may as well get the customer service points by taking that $50 as well. As such it is only a minor inconvenience if someone gets a hold of your card, most of which is related to waiting for them to mail you a new one. Because of this people don't care about chip and pin being more secure: security was not their problem. This is also a factor in why the US is much more likely to use a credit card: there are no anecdotes about someone losing a lot of money because of their card.
By contrast in Europe you were liable for all amounts charged on your card before you report it, even if you had no way to know about the charge. Since the credit card companies didn't have to take a large risk they typically didn't agree to take it on. As such a credit card is much riskier, and so it is prudent to not use your cards if you have a different option. When chip and pin came out consumers were interested because it gave them some ability to limit their loss: their chip/pin card could be lost without the potential of great loss.
Note that the above is historical, and like all generalizations is false in some way. Laws change all the time which means the current reality is probably different - but the historical reality is still shaping our world. Europe is not a country, each country in Europe always had their own laws which differed in some way from the next.
That's true only if you or the credit card company notice the fraudulent transactions and act on them within the limited grace period, which I believe is something like 3 months.
Many people don't actually keep their receipts or reconcile them with their credit card statement. So unless they get an unexpectedly huge credit card bill, they might not even notice that they were victims of fraud and in that case the "0 liability" credit card policies are worthless, because they get defrauded anyway.