Does the fiat leak website take into account when someone sells bitcoin for fiat? otherwise its pretty useless...
Every trade has a buyer and a seller.
This is true, but consider this...If someone is buying a bitcoin from a seller who is selling for a loss (fiat loss), the flow is reversed (fiat flowing out of bitcoin rather than into it), and I'm not sure that website takes that into account?
That sounds like nonsense. Bitcoin is not a fiat reservoir. Money flows into exchanges to buy, and then flows out to the seller. Bitcoins transfer ownership, fiat transfers ownership. Nothing was created or destroyed.
And no, that site doesn't consider individual traders' profits and losses. This information is not public.