> In Chinese apps, I can post photos, message my friends, order food, call an uber, pay transactions, all from the same app
I don't see how this statement says anything about UI information density.
This is just a super app with monopoly over the market. Last I checked (and it's been a while if I'm being honest) WeChat just looked like a custom launcher for other views/apps that all happen to be hosted and controlled by the one company. That's like saying "Android is super dense. I can post photos, message my friends, order food, call an uber, pay transactions, all from the same device"
Pretty sure Facebook or Google would love to be that super app for US/Europe/rest of the world. However, you'd probably shout "monopoly, lock-in, anti-trust, market manipulation" if any single vendor actually tried and succeeded in that. For good reasons too.
In Chinese apps, I can post photos, message my friends, order food, call an uber, pay transactions, all from the same app