So, now I have a question: What is 'real time coverage'?

Like you, I'm not sure where I'd use feature that lets you nudge a line and then when you get to the end, it goes back to pre-nudge condition. I can only guess that someone with an RTK system may have a use for the feature but when I'm nudging it's due to satellite drift and I've never seen that go away when I get to a headland.