I'm surprised I haven't seen this discussed more, but #musk pushing the #x app onto #twitter isn't some new idea. It's a mediocre idea for a bank he had like 24 years ago that became #PayPal.
The rumour is when he tried to force PayPal into the basic model he's proposing for Twitter (the "everything" app is bluster--he just wants to make a crypto bank out of Twitter) they booted him because they didn't want to be another giant bank. Elon is just making a bank.