Generally the vehicle or machine is operating in a hazardous location, like along a highway. While rotating lights put on a good show, it is easy to become complacent as you approach the hazard as you have seen the glowing rotating light for some distance and know exactly where it is. The strobe on the other hand, flashes and then disappears into the background until the next flash. A typical two beam rotator draws 5.6 amps while a strobe light of equal effect draws as little as 1.75 amps average current. The strobe light would consume only about one third of the same batteries capacity.
Strobe lights contain no moving parts.
Circuits are encapsulated in hard epoxy providing excellent environmental protection. High vibration environments tend to shorten an incandescent bulbs life while strobe tubes are not effected.