The point being that if Britain can hit The Falklands by air, they for sure, we can hit mainland Argentina.
Not really though, I think both we and the Argentinians realised that the chances of a Vulcan raid to the mainland was pretty much a non starter. The Argentinian Air force had some pretty sophisticated radar that would have picked it up miles away, and whilst the Mirages and Daggers weren't much cop over the Falklands they'd have had no worries shooting down a Vulcan..
The whole point of sending the Vulcan down there just to bomb an airfield was to show Argentina that we were more than capable of putting a 1.1megaton blue steel rocket propelled device right down their throats.
That's why we did it.