Why joules ? Joules is a quantity that translates across all energy storage types.
Why energy ? Because the need for energy ignores bankster propaganda and media manipulation.
The need for energy is proportional to the size of an economy, that is one of the metrics that is used to estimate the black markets, the unaccounted for electricity that is used.
It is a general indirect method to measure it because of the fact that energy/GDP, it can be used in the case of busting miners and weed planters of course, but then they often use-
thermal cameras from helicopters and checking for electricity spikes in the grid, but what I describe is a tool economists use to estimate the size of the informal economy as a whole.