The past 10 days have proven that cash is still the preferred payment method in Bangkok and Singapore. Credit cards are also widely accepted in Singapore, whereas only more commercial merchants in Bangkok accept plastic. There have been no opportunities for mobile payments in either destination, even though Starbucks teased me with the mobile app scanners in-store! Sadly, it was not possible to use the app abroad.
So, for now, at home and in these parts of Southeast Asia, ca$h remains king!