One of the side effects of the new tech-tree system is that not all buildings are appropriately "obsoleted" when they should be.  One example is the Altarian tech tree, where you go from entertainment centers, to temples, to healing pools... and all three remain in your tech tree, because the game doesn't recognize them as upgrades to eachother.

Invasions also net you "useless" techs like that -- I frequently end up with 2 / 3 sets of economy buildings, and only want to use stock exchange because the others are, quite simply, inferior.