It is not useless and I wish that they released it earlier. For example, I recently had a second 13% TD guardian done by my Sculptor but to place it I would have to sacrifice 14% TH guardian. I did not want to do that rebalancing until I upgrade my Sco to level 9 and Zookas to level 21. So I had to crush that guardian. I would put it into storage and place once I am ready to do rebalancing. The same goes with ice MPs or anything else: you can work out through the power stones and then place the best but not needed yet statues into storage. Two slots is sufficient for many uses and 5 is only needed for very high VP level players in order to perform ice to magma/dark guardian swapping on a daily basis (or something like that).