If the president was gracious enough to decline payment for offices leased by the government in Trump Tower, it's likely due to the fact that government expenditures are public record and taxpayers would be able to see just how exorbitant his decision to work out of Manhattan really is. Additionally, by not taking payment directly, he is able to write off the price of the offices as a charitable contribution under section 170(c) of the Internal Revenue Code, benefiting by way of a tax deduction hidden in documents that we all know by now will likely never be part of the public record.