While WeChat is somewhat more advanced then its rivals, the reason it works is because Chinese businesses are less 'sophisticated' than western ones and much more human based. WeChat is to a large extent a phone call replacement, which is especially useful in a country of multiple languages and dialects but a common written one. Western messaging services are mainly replacing things like text messages and other instant messengers not e-mail. (e-mail is probably still the de facto most insecure protocol on the internet and should be replaced).