They wouldn't get to keep the cash either way, but it could do some interesting things if pushed in certain directions.
Such investments essentially allow high brackets tax payers to get interests on their taxes...
Plus, it means that unlike lower income tax payers, higher income tax payers get to decide which government programs their taxes are spent on. Very undemocratic.
An example : to help service employment, house employee's wages are tax deductible, in France. Which concretely means that if you pay enough taxes, your babysitters eventually cost you half their wages ; that's very regressive... Un roi sans divertissement est un homme plein de misères
