Yeah, I remember when Democrats wasted all that money in solid Republican states like Virginia and Colorado in 2008.
I don't really think you can compare VA and CO to GA. My evidence for this is looking at the 2004 results. CO was not a solid Republican state in 04, Bush won it 51-47, and while VA did give Bush a larger 53-45 margin, Bush won GA 57-41. I doubt that the 04 to 08 swing in VA will be replicated in GA considering that the environment for the Dems will not be nearly as good in 16.
Sometimes a hail mary is more accurately an investment in the future if the rest of the map is favorable