Isn't WeChat the app that is used for everything in China? It's not just a communication app. So yes, there is more than one reason for it. A lot of its probably required to perform so many functions, but also they are collecting everything on you too.
Yeah it does quite literally everything, so the permissions make a bit more sense. For me, living in China, I'd be crippled not having it. I use it to book travel, pay bills, talk, register for services, book a doctor's appointment, pay for goods, use it as a login for other apps. The list goes on ad infinitum. If you're using it as a chat app, you're paying Ferrari price (in user data) for an electric scooter.