Is "blooming" cocoa necessary in baked goods? I've read that dissolving cocoa in hot liquids is supposed to make it release its flavors and make it taste more chocolate-y.  This sounds useful for things like frostings or no-bake cookies, but does it make a difference if you're going to cook the final product (eg. chocolate cake)?

I tried an A/B test with chocolate cupcakes, but none of the tasters could tell there was a difference.  Did I mess up my test or is there really no difference?
The interaction between the liquid and the cocoa during the blooming process and inside of the cupcake batter during baking is not the same.

During blooming, there is only the liquid and the cocoa interacting in a free-flowing liquid matrix, and in the baking, both liquid and cocoa are trapped in a coloidal matrix. If you bloom before you add to the batter, you make the aromatics in the cocoa more available for the taster. 

Keep in mind that not everyone has the sensory acuity to notice the difference, so it is up to you if you want to invest the time for that