WeChat keeps statistics on its data usage and you can easily review and see how bad of good it is compared to its competitors. WhatsApp does not have this info, but when I used 3rd part tools to measure my WhatsApp data usage over a week, I realised WeChat uses about 40% less data than WhatsApp.
The assistant general manager of Wechat products division, Zeng Ming says, because mobile payment involves the users property security, Wechat will strictly verify the qualifications of the merchants, commodity and experience. In addition, because Wechat payment has just been introduced and still needs to be perfected, Wechat will audit information more clearly, the process will be improved. Wechat payment therefore is not within nine open interfaces.