There is no requirement to use the two components of DFS together; it is perfectly possible to use the logical namespace component without using DFS file replication, and it is perfectly possible to use file replication between servers without combining them into one namespace.
In 2016, the majority (51%) of the 8.4 million barrels per day (b/d) of crude oil produced in the Lower 48 states was light oil, or less dense oil with an API gravity of 40.1 or above. Light oil also made up more than half of the oil produced in 2015. API gravity is measured as the inverse of the density of a petroleum liquid relative to water. The higher the API gravity, the lower the density of the petroleum liquid, so light oils have high API gravities.
As shown above, API SA oil was the first in the API Service Classification for gasoline motor oils. These oils were formulated for use in vehicles built prior to 1930. That's right, motor oil made for cars built nearly 80 years ago!