[benj111]

>My Hyundai Ionic 6 rolling battery costs 50-60k. Spending a cycle of it's battery is not a discardable cost

Problem is we don't have good data on actual costs. So we don't know if we're talking about something substantial or something hypothetical. Absent that data I think my comment is fair.

>I presume you deduct more than half of the rolling battery capacity out there

No. We are talking about 10% of battery capacity so your battery at 80% would only need to go down to 70%.

A problem we have in the UK at the moment is that we have gas turbines running even if not needed just incase the wind suddenly drops. It takes (or can take) about an hour to spin up a turbine from cold. So a battery supply that could cover that hour would mean we could use a lot less gas. Most of the time it isn't even used, and if it is, most probably won't use that full 10% and once the gas turbines have spun up it could recharge the batteries.

To link it back to the earlier comment, even if the maths is bad for EV as battery storage, you can still use it as battery of last resort. It would be expensive, so ev owners would still be up on the deal, but there would be a system on place to actually use them when actually needed.