Indeed, semantics. I prefer "free energy" because it is energy We can access and not have to pay for. Once the right setup has been started, no further payments are needed to have abundant energy flowing.

We pay for the energy to start it, but get more energy in return, and that overunity is free.

Anyway, the point is that with it, We do not have to account for Our energy added. i.e., We don't need money, the foundational function of which is to account for the energy We add into a system.

Once money is obsolete, everything is free.