“Oh, we’ll store your unfinished thoughts, privately typed into a text box, on the off-chance that you want to continue writing it on another device. And no, we won’t ask you nor give you any semblance of true privacy.”
Sounds good.
"Privately typed" is a bit of a stretch, frankly speaking. That text box literally exists to send your texts to a remote entity.
It is also super common on e-commerce websites that will then send you an email about a cart you started to the point of adding an email but then abandoned.