I would have assumed it would be relevant to supply chains. I too do not understand its relevance to consumption. It seems like you could substantially increase your material footprint by digging two holes and swapping the soil, which is a little silly.

That being said, GDP is also a silly measure: I pay you a billion dollars to slap yourself, you pay me a billion dollars to stomp on my own foot, and we've just raised GDP by $2bn. Despite its ridiculous nature, in practice it seems to correlate with the things we do care about.