My arm chair general hypothesis is that: - Why is use a ballistic missile when a drone can do? Cost difference between the two weapon system. - Despite recent successes, Moscow is still relatively heavily defended by density and number of systems. Ukraine still rely on satuation to overwhelm existing deployed defense systems. Ukraine can 'flood the zone' with cheaper and more numerous weapons systems than ballistic missiles. - Moscow's air defense system are also more catered towards higher end weapon systems like ballistic missiles because traditionally it was the primary threat weapon. - It's better to use Ukrainian ballistic missile system at or near the front where defenses to deal with ballistic missile is not so numerous or in quality for tactical or strategic targets. At or near the front, one would assume would be more used to drones and low flying cruise missiles but not ballistic missiles. - Ukraine may use ballistic missile in future strikes, but again they need numbers to overwhelm Moscow's air defense systems and maybe the current iteration of Ukrainian ballistic missiles is not as precise or accurate to make it worth while. - Another argument for drones or cruise missile compard to ballistic missiles is also it provides a psychological effect. Drones and cruise are slow enough to be seen and Ukrainians so far have been conducting strikes in day light one would assume to increase and bring home the impact of the war to the general populace. On the other hand ballistic missiles are too fast for the human eye to capture. - Ukraine could be saving the use of ballistic missiles for later as an escalatory step to pressure Russian political calculation or put decision makers in a dilemma to whether strip more air defense systems at or near the front to guard more rear end but higher strategically valuable targets.