Islands like Tonga and those in the Solomon Sea owe their existence to this occurrence. But perhaps more importantly Australia is indebted to the plugging. Apparently the plugging allowed Australia to migrate much further north than it could have under "normal" circumstances. Australia would have been an cold to cool land with much snow expect for the very northern parts say around Darwin.
The fact Australia was habitable allowed for English migration and culturalization. The island continent allowed the British to extend there empire and by effect common law and the ideals of human liberty (even if they were not practiced all the time). Australia has proven to be a major player in the Anglosphere leading efforts in World War I, World War II, and today's Global War on Terrorism. Without the collapse of Izanagi Ridge who knows what the world today would be like physically and culturally.