Same for some SEA countries (Malaysia & Singapore), whatsapp (some includes other popular messaging apps such as WeChat, FB messenger) messages/calls does not c

Same for some SEA countries (Malaysia & Singapore), whatsapp (some includes other popular messaging apps such as WeChat, FB messenger) messages/calls does not count toward your data usage for most telcos and it is the main way people communicate, Whatsapp basically replaced SMS there when it was launched.