WeChat became one of the main mobile consumer platforms in China. It seems weird/different than elsewhere, because it's a chat app. It's basically just a different UX for the homescreen.
Comparing WeChat to WhatsApp on feature count is big time apples to oranges.
Not going to go into detail as I'm sure you know how to use Google.
Wechat isn't simply chat. It has grown into a platform that has empowered it's users to partake in a growing ecommerce industry. It also has p2p payments which is hugely popular.
If there were only 1 channel on TV, that channel would be very popular!
If Google or Facebook were given a monopoly on chat by the US government, and hardly anyone had credit cards, then their wallets would be universally popular too.
WeChat isn't going to get much market penetration outside of China because it's just not very good. At least that's my opinion, as someone who's forced it use it in China.
Comparing WeChat to WhatsApp on feature count is big time apples to oranges.