In some situations it’s useful to be able to add content like this orange guides for comments or for documenting flows that should not be captured by the Artboard. In Figma you can hold spacebar to avoid overlaping elements to get trapped by the frame or even to be able to move outside without being released (useful when animating in/out elements in transitions).
And the icing on the cake it would beto be able to connect artboards with flow arrows (similar to the way prototype connectors work but for Artboards and elements to be able to arrange elements without having to re-arrange the connectors (I now, it may be way out of scope, but one never knows)
