That's the difference between "you have to trust WeChat" and "anyone can read your chats". Of course you may not personally be interested because you don't personally use WeChat, but for the billion active users who do, I think it should matter.
- against random 3rd party, even WeChat is ok
- against random black hats, most of chat software is ok, maybe even WeChat
- against gov agencies, nothing is going to protect you
When I am in China, i happily use WeChat including the gazillion of services available through it. Buying metro pass, ordering food, getting a battery pack and so on.
Btw no country could replicate this outside of China, which is an interesting phenomenon. We have endless ads including actual scams and malware distributed by Google Ads yet I cannot buy train tickets in the EU through a single app and order food as well, let alone getting a cab. It would be great though.