Why is it important for Scrooge to visit the miners, the lighthouse keepers, and the sailors?

The Ghost of Christmas Present takes Scrooge to see groups of people in isolated places: miners on a moor; lighthouse keepers; and sailors out at sea. Although they are alone they share the spirit and warmth of Christmas. Scrooge has the ability to be with friends and family, like his nephew Fred, but rejects them preferring to be alone.