We don't have high capacity (centralised nor distributed) grid scale batteries in many places yet.
What it boils down it is, even if this works, which I doubt, 20% transmission loss makes this a niche market at best.
NZ is proposing to go fully renewable by 2030 as well as promoting higher EV targets for 2023. We already import many right-hand drive Nissan Leafs reaching their 7-year EOL from Japan, so re-purposed batteries for off-grid storage will become very cost effective in short order.
Our aluminium smelter is also slated to close in a year which frees up about 10% - 15% of national electricity, and we have pumped storage for day/night loads separate from hydro.
Given the political climate here, niche opportunities abound imo.