I'm no rocket scientist

but based on a couple of notes from wiki, they are a fun to have pointless to research weapon if we are talking WW2, despite the below fact regarding the cost of the project the other problem with the V2's were not having a proximity fuse which limited their effectiveness when they hit and though they were in relative terms much less accurate than bomb's dropping from 25 or 30 thousand feet in the air they were to expensive to saturate a target area to making them effective in their design.
The German V-weapons (V-1 and V-2) cost the equivalent of around USD $40 billion (2015 dollars), which was 50 per cent more than the
Manhattan Project that produced the atomic bomb.
[11]:178 6,048 V-2s were built, at a cost of approximately 100,000
Reichsmarks (GB£2,370,000 (2011)) each; 3,225 were launched.
Personally, late game like if I'm in 46' and winning as Germany maybe I'll go down the rocket path but otherwise strategic bombers without the A bomb were a more effective measure from a military perspective in providing the results. I'm not going into the A bomb debate but it as well for it's cost can be just as easily argued not to be the war winning weapon in game terms unless your the US, SU, or UK and if money were a factor I would say the UK's own bombs would been developed deeply with the US because of their economic situation by 1944-45.