sticker: gifs and emojis all shares the same sticker format. It has natively features for taking, editing and converting photos and videos directly into stickers. Generally, i find memes work a lot better in wechat.

reliability: voice and video calling is buttery smooth. I've taken wechat calls internationally between china, taiwan, us, canada, australia and france. The service is always great even in some rural areas.

consistency: it works on almost all phones of all price ranges. Maybe it's because lower tier phones are of chinese brands and they have closer collaboration with wechat. The point is that wechat works the same on a $100 dollar phone as it does the iphone.

convenience: this one is domestic to china. wechat has mini programs, which are basically web services that make native app obsolete. For example, there is an wechat version of airBNB and it works exactly like the native app. Wechat handles all of the authentication and transaction. There is no need to register for anything!