This. And another scenario. You have some fiat business, company, having some profits there. You might want to convert some of it to Bitcoin and put Bitcoin on balance sheet of the company. You will need to buy that Bitcoin from company bank account. Alternative would be to pay out dividends to yourself as an owner and then you can do P2P cash trade and buy Bitcoin that way, but that will involve forced paying of income tax to the government, so it's not in your interests.