Well, it's only going to become a greater issue as people live longer and longer lives but the last years of those lives are progressively worse and more drawn out. Maybe it's simplistic or overly emotional, but what's the point in living in suffering? It's placing a higher value on simply being alive than on living well.
I think there's a general sentiment to leave things to unfold as they will, perhaps as "nature" intended and to not interfere. But a hands-off approach to managing life and death is still a chosen way of managing it, and arguably not a terribly good way.
You're glad your granny didn't have to suffer unnecessarily. From my own anecdotal experience, we watched my grandfather slowly rot away in a nursing home for the last years of life - physically, that is; he was sharp as a knife until days before passing. I can only look at that and wonder what the point is.
Also, did they give her chocolate? I heard they do after they've administered the medicine. Seems like a nice way to end it.