they can be used as cash in the States. Safe and easy to carry.. the only problem is you have to pay 1% (or 1.5%) commission to American Express. I saw some Ads in the States, saying American Express now comes out with a card, as a substitute of the cheque..i'm not sure if SG offices start to use this new product.. check with the banks in SG..

i bought my traveler's cheque in Changi airport, just look for the American Express sign in the money exchange counter..