Grey areas

In case you can't read the labels, the left one says "Satan's Kingdom", and the right one says "God's Kingdom". I relate a vignette relating to this diagram on CatE, here. The questions are:

1. How far does Satan's Kingdom extend?
2. How far does God's Kingdom extend?
3. Are either of the first 2 questions relevant, and/or more important than the other question?
4. Does this diagram represent reality in any way? Why or why not?