The range argument and the accuracy seem to be more prevalent than enemy characteristics, although that factors in as well.
All of the German V weapons were quite brilliantly engineered but slave labor manufactured disasters of accuracy. With a range of 250km and a target deviation of up to 20km they were mostly terror weapons, not precision instruments. As such they impressed more those people that feared the SS was coming than those who knew what the Wehrmacht had left. The Soviet Union itself was simply out of range when the weapons were ready, especially when you look at where the undamaged cities and production centers were located by that time.
If you look at the hit rate for the fairly large target of Antwerp – contrary to public imagination the main target of V2s – it becomes apparent in how uninterrupted the shipping was how inefficient the use of Aggregat4 would have been on devastated Eastern Europe cities or largely dispersed Soviet troops. In Antwerp they targeted the harbour, but hit cinemas. All of the long range V-weapons managed to kill 'only' 15386 enemy civilians and 47028 people were injured by those weapons.
Concerning Warsaw as a supposed staging area:
The Germans then razed Warsaw to the ground. Hitler, ignoring the agreed terms of the capitulation, ordered the entire city to be razed to the ground and the library and museum collections taken to Germany or burned.
Hölsken calculates that in total 22384 V1 and 3170 V2 were fired at the enemy. Curiously 11 V2 were targeted on German soil. In fairly short distance one of the prime targets of strategic importance was a certain bridge at Remagen. None of the V2 used managed to hit that target.
Dieter Hölsken: "Die V-Waffen. Entwicklung und Einsatzgrundsätze", Militärgeschichtliche Mitteilungen; Freiburg Bd. 0, Ausg. 2, (Jan 1, 1985): 95. p 116.
The weapons were most effective in killing the slaves used to manufacture them and as a propaganda tool, and are still used as such in recent documentaries that simply regurgitate Nazi propaganda.