What Does Surveillance and Reconnaissance (ISR) from the Reaper's Unblinking

What does surveillance and reconnaissance (ISR) from the Reaper's unblinking eyes allow for?

A) It allows the reaper to fly in the outer atmosphere.
B) They save American lives but are more expensive than their inhabited counterparts.
C) The Reaper is actually cheaper but usually it is not as effective.
D) They can strike with enough precision to minimize or even avoid civilian casualties and unnecessary damage.