"You wouldn't want to count the carbon emissions of making the appliances used to keep the warehouse clean too because with that procedure the carbon emissions of anything would be infinite." Problem is that this is the kind of loopholes orgs use to be able to get a lower number on reports. See country selling their waste to poorer countries. You don't have to necessarily fully map the true production chain but not counting the emissions of the tools used to produce, store and maintain the smartphones smells like cheating to me. All those tools will be contributing to carbon emissions and setting an arbitrary line only serves to push the responsibility of those emissions with someone else which is how we got into this whole environmental mess in the first place.

Obvious is just shorthand for unsubstantiated beliefs ime. What does "quite small" even mean? The iPhone carbon footprint is likely the lowest of all smartphones given Apple's efforts to look as green as possible. Your regular smartphone has almost double the carbot footprint at around 80kg. When you consider that most non-iPhone non-flagship smartphones become virtual bricks after 2-3 years, 80kg is a lot to me.