It is not a battery in the physical sense because it does not store energy. What it does is, it allows you to transfer the economic utility of cheap local energy to regions where energy is more in demand. Although, as the article itself highlights, this could also be done more efficiently with aluminum smelting, and other processes that are energy intensive but don't require much infrastructure.

From a purely financial point of view I suspect maintaining a bitcoin mining operation in remote areas is harder and requires more frequent upgrades than if you were doing a more traditional manufacturing process.