> It's not like detergent is something you need to order every week

That's exactly why this is useful. It's something I forget to buy at the store because I run out so rarely. Right now while I'm doing my laundry if I notice I'm below about a third I'll hit the button.

Before I'd almost always realize I was out of detergent mid-washing, undoubtedly the night before some important meeting, and have to run to the store in the middle of the night.

Maybe, but the advice to have two containers of stuff like that seems like a good idea. The only issue I have with that is that I misplace the backup and then I buy another and accidentally have 3.

Does that really justify eventual electronic waste, an inefficient delivery and packaging material?

Leave the empty bottle by the doorway or in your car or something until you remember.