Currently canvas.drawPoints throws UnimplementedError, but it's useful for drawing points/lines/polygons on a Canvas. For now my use is mostly for debugging - I'm creating a renderer for Tiled maps and it allows poionts/polylines/polygons to defined as areas on the map (eg. for triggering things, or making NPC paths) and it's very useful to turn on rendering of them. (I'm sure there a non-debug uses, but that's all I have right now :-))