I think geographic dispersion of batteries is going to be a big plus. If the "battery" is a giant lake or a big plant with a spinning mass, the power has to be transmitted from that facility to the end user over the grid

Putting a ton of smaller chemical batteries at distribution substations means when the grid is at the peak, you can cover that peak without transmitting that power over the transmission system. Putting the battery near the consumer will take a big load off of the transmission system which as much of a bottleneck as the lack of generating facilities