that would be wild. that doesn't sound valuable enough to bother with, even for feeding a shitty LLM.
this is probably bad evidence but every ui I've interacted with is trying to preserve data and only send info once it seems certain you're posting. even reddit doesn't count your comments as edited until you make changes several minutes after commenting. since so many of these services seem to store actions in a buffer before sending, I don't think that's worth the data cost of live recording your drafts.
your keyboard app on mobile however.... yeah that shit is an info harvest on the scale I think few things are