What is the importance of the Juan Fernández Islands as noted in the nonfiction book, Two Years Before the Mast?

The brig Pilgrim's first opportunity to drop anchor in 103 days after leaving Boston, MA, the Juan Fernández Islands are located 300 miles west of Valparaíso, Chile, in the Pacific Ocean. Author Richard Henry Dana, Jr. links them with Daniel Defoe's novel, Robinson Crusoe, where the real-life inspiration for the character spent several years. This gives him a fond association that balances the meagerness of the Chilean settlement being built by convict labor and filled with "loafers." The town is set against high, wooded mountains inland. Convicts exiled from Valparaiso perform manual labor.