a) It can occur over time and place - i.e. I can communicate a basis point (tiny, a long) to you, and 3 days later you can look at exactly what I saw b)It does

a) It can occur over time and place - i.e. I can communicate a basis point (tiny, a long) to you, and 3 days later you can look at exactly what I saw b)It doesn't require any coordination, read locks, MVCC etc