Would have been better to run the script that edits posts, just to fuck with the data.
China and Facebook would probably buy it for their own profile databases on every person on the planet.
Chances of that though are unlikely. Both are more worried about short term things. For China spotting dissent and trends on the fly. For Facebook selling ads more accurately.
Apple gets your voice recordings which for various privacy laws they can’t resell. “Yay wiretap laws from the 50s”
As for typing, a quick search, apple support claims that the keyboard cache is only used for autocorrect purposes. How often you use a word and how you like to spell it.
Having it function as a keylogger would give them a headache, from data use, battery life, hackers exploiting it, etc.
And of course the warnings seem targeted at third party keyboards who can add on extra feature beyond IOS barebones.