Earlier quoted context omitted.
In store: you need to have someone stock the shelves, someone walk through the store and pick groceries, and someone handle the payment in person. Chance of infection: depends how long since someone coughed in the store. Online: you need someone to stock the orders and wait for people to drive up for curbside pickup. Chance of infection: low. Surely the second option is both safer and more efficient?
Probably different regions but none of my grocery stores do online like that. They have someone walk the aisles and shop like a regular shopper, and check-out at the cash register like a regular shopper. They will even give you their receipt to verify the order. You're just offloading the risk of infection to someone being paid to grab groceries.
Still, if the stores handle this themselves - it's much more feasible to take extra precautions - from using a locker room to change into a uniform (not bringing outdoor/home clothes into the store) - to using disposable gloves etc.
Ideally, stores would offer only pickup and delivery - and not allow in-store shopping at all.
Would probably make sense to increase staff as needed, as any additional staff needs would scale with increase in revenue.