In most cases, yes. Nevertheless, credit cards are not as common in Malaysia as they are in Europe or the US. Many rural areas as well as small shops and markets do not accept any credit cards, so having cash on you is always a good idea. In addition, withdrawal fees (conversion, ATM fees) can start to add up and become significant, so arranging for an account at a local bank will be necessary if you really plan to spend several months a year there. Many rural areas as well as small stores and markets do not accept credit cards, so it is always a good idea to carry some cash.