Either way, people forget about this, because if you have any sort of power generation, doesn't matter the method, if you go over capacity, you have brownouts/blackouts/grid failure/etc. What is deployed now, for the most part, is sufficient genset capacity to ramp into peak load, and most of it is under-utilized the majority of the time. Batteries eventually pay for themselves because of this, as they allow for peak load handling in addition to allowing generating capacity to stay online and remain profitable outside of peak load events. It really is revolutionary.
More or less, gridscale batteries are what dams/reservoirs were to water systems, and if you consider the impact of us as a species being able to save water for later use at-will, the promise we're looking at is going to really change the way we live.