As you mentioned with tag [place=island](https://wiki.openstreetmap.org/wiki/Tag:place%3Disland) it should not be used on a relation but to be drawn as a counterclockwise area (because water is always on the right hand side). Relation should be created when the coastline is split into several smaller segments, for example, for creating smaller admin divisions or coastline of the island has more than 2000 nodes (for very detailed or large islands). Then you need a relation for the whole island. In some cases, the relation is used to group some close islands which have the same name but are not archipelagos. 
Another thing I want to point out: I am not saying that what you did is a unique example, but per OSM Wiki and some general mapping rules, we should not use relations for these simple small islands. I just stumped upon your edits because there is a fair amount of them, and I was in the region at the moment. 
Also, read this: Relations are not categories - OpenStreetMap Wiki

