What happened was when he went to Shanghai he had to use WeChat and he loved it.
Super apps will never take off in the rest of the world. I mean for fucks sake you can't even get Americans to agree to use WhatsApp. Like the only reason so many people use Instagram is because Facebook bought all of the competition, including Instagram.
There's also the issue is security. WeChat, for all intents and purposes, is a gov app. I have to use it for so many government things, especially during the zero COVID era. This would imply it gets state backing for not only finances but security too. Twitter breaks if a fraction of the user base logs in. Now imagine it having everyone's stored financial information. Twitter would be getting hacked daily.
While I'm sure EU and US gov would like a super app i don't think they'd sponsor this one. Especially since Elon's a well known liar/grifter who will cowtow to any foreign leaders to raise the stock if Tesla by .0000001%. He's easily bought, which is funny since he's supposed to be the world's richest man.
Finally, FB already does this. FB not only has a market but they have a financial payment system. I used it when one website didn't accept Paypal. Facebook even has a built in Amazon like feature that no one uses, or it was disabled. I used to buy from people's Facebook stores. In fact this was how a lot of Japanese artist and game studios would sell stuff to the west for a bit. So, we have a working super app with these features already and no one uses it because it's for boomers.
Hell, Facebook was running miniapps before WeChat was even a thought. Actually Facebook did a lot of this before WeChat now that i think about it. Twitter can't even display ads unless they're tweets because their system will fucking crash and burn displaying anything other than a Twitter feed.