Well, if the energy wasn't actually used, or destroyed, then this "connection to the real world" would just be fake.

The work done produced a store of value that cannot be tampered with. If we say Bitcoin produces nothing of use, we should also say banks are doing nothing of value at all. But that is not entirely true. Keeping track of who owns what is an essential part of our society. Doing that, without having to trust a single powerful group of individuals, is of immense value from my perspective.

Besides that, the goal of many "Bitcoiners" is to use energy, that would be lost otherwise. Currently, it is a huge problem of renewable energy sources that the energy output is somewhat constant, but our usage is very much fluctuating (night vs day etc.). Storing energy on its own is very expensive and totally inefficient. Using that energy to power this decentralized record of who owns what is an amazing idea to me.