I expect typical smart cards like the one in your credit card are harder to crack than the raspberry pi was. Those cards are (or were) also used in TV set-top boxes and back in the day, there was a decades-long arms race between the chip makers and cable TV pirates. The TV pirates were also willing to make large expenditures to crack the chips so they could clone them and sell the clones. There's more about this in Ross Anderson's book "Security Engineering".