The point wouldn't be just for backup during outages. It would be growing your kWh of storage and doing daily TOU optimization. That increases the charge / discharge profile by a lot.

Though for an 80 kWh or larger battery, you're only likely to store up and discharge 10-ish per day maybe this way? (Assuming you have actual dedicated BESS, and this is supplementing that). Still that's ~30 cycles per year, which is nothing in the grand scheme of a vehicle battery.