Why are there full viewport updates?

[JamesDeAntonis]

I noticed here that you have

self.setViewportUpdateMode(QtWidgets.QGraphicsView.FullViewportUpdate)

is it dangerous to set bounding rect viewport update instead?

self.setViewportUpdateMode(QtWidgets.QGraphicsView.BoundingRectViewportUpdate)

When dragging nodes, I noticed the full updates cause like 70 (I think) unnecessary repaints on top of the expected path repaints. This was causing lagginess for me, especially when other animations are happening at the same time