Craig,
I agree that they were a stepping stone, and if they had been given more time they very likely would have developed them into a more powerful and accurate weapon. That the same is true with the V-2 can’t be argued – the lessons the Germans learned from the V-2 were applied by both the US and USSR to their own missile programs.
However, in my opinion, in spite of what the Germans learned from deploying these weapons, I’d have to say they were a waste because they would have been better off using those resources on other things. If they had these weapons, say, two years earlier than they did then perhaps they might have made more of an impact (so to speak). As it was, they didn’t have more time and they weren’t in any shape by 1944 to be spending resources on something that in the short term was going to have little military value and was going to take years to be perfected.
We’ve never had anyone build any of these in any of our games – usually the game’s over by the time Germany can build them – but I think each one of these built in a game ought to count as a unit against the aircraft build limits to properly reflect the resources that were diverted into these instead of other areas. I also think giving each one a D6 is too high.