The main point of the comparison is to illustrate how the economy is short of some inputs, like electricity, but there is slack in other areas, such as employment. In these conditions, what the MPC is trying to gauge is the space to satisfy additional demand and follow through on what that means for monetary policy.
The difficult part, for the MPC, is judging how much we can do to help on the demand side when the supply side of the economy is in such a perilous state. In common with many other central banks, we are flexible inflation targeters.