nellie people don't usually ask for an edit button because they've made an ordinary spelling error like missing a consonant out. No one minds about that sort of thing anyway.
It's usually when they've completely misinterpreted someone else's post and want to rewrite it, or when autocorrect on their iPad has gone beserk and changed something innocuous to something completely different.
For example, my phone has just tried to change 'completely' into 'mole test' and insert 'could' before 'completely'
I think you would have noticed that, wouldn't you? But I could easily have just posted without noticing, and that's when Preview is useful.
(Phone is really annoyed with me now & changed 'noticing' to 'noted' as well)