Complex sentence: Its main importance is as a port as it has the only harbour on Iceland's southern coastline between Grindavík in the west and Höfn in the east, and it serves as one of two departure points for ferries to the Vestmannaeyjar archipelago.
Split into simpler sentences: Its main importance is as a port as it has the only harbour on Iceland's southern coastline between Grindavík in the west and Höfn in the east. It is also one of two departure points for ferries to the Vestmannaeyjar archipelago.