I have a 2 person household, and I probably buy those above mentioned things like 2 times a year at most, so an order button for a single product would be waste

I have a 2 person household, and I probably buy those above mentioned things like 2 times a year at most, so an order button for a single product would be wasteful. For people who use a lot of laundry detergent, I would imagine those people would be shopping a lot anyways for everything else they use a lot of, so it wouldn't be inconvenient to manual reorder online or at the store when they're already doing a mass order, and it might be confusing to have a mix of things on auto-reorder, buttons, and manual order.