Most places where you can use a credit card in Europe require you to use the chip (usually with a PIN).
In every case were I used a USA chip card (with no PIN), the card reader prompted for a signature, so it was no problem.
Though I really don't understand why USA issuers and merchants went with a chip-only system, seems like it would have been trivial to allow PIN too.
Though even Chip and PIN only fights a small portion of the fraud - every time I've experienced credit card fraud, it's been with internet purchases. Amex used to let me generate a temporary card number for each merchant, I used that all the time, but they dropped the service for some reason.