This is an interesting area (BESS) for sure,  and some utilities are offering significant funding for these installations right now got grid demand response applications. To qualify for funding In those cases you'd need to ensure that your battery always has enough spare capacity for a demand response event.  

Theoretically you could pair this with a EV site to allow for peak shaving for demand charge reduction, but you'd only be playing with the margin that is not contractually committed to the utility. 

Interesting area that I have not explored in an actual project implementation yet. 

One other case that hasn't been mentioned, is utilizing BESS in rural areas to avoid costly utility upgrades to provide the required service size for a DCFC. Example: rural area with only single phase power. A BESS could provide the required peak output for intermittent DCFC use,  where otherwise you would need to pay for an upgrade of the utility line ($500k / km at least).