First, it signals that Andreessen is comfortable with the state of this technology from a liability point of view.
For trial lawyers this means your search for software writer liability reached a major roadblock. No one is going to let you look inside the OS to see the system itself.
Second, this signaled that the developing civilian market for drones is developed enough beyond mere speculation to permit some sort of valuation.
Third, it shows that Google is very carefully considering integration of flying robots with its driverless cars.