Clearly it is for the great majority of people, but what I would throw in is that the top percentage of people, for whom it's not truly a consumption tax, are very important in economic terms. Savings rates rise very steeply with income towards the top of the income distribution. So the people who are very active in the markets, who are saving a very high fraction of their income, who have a lot of income to save--they are beyond the contribution limits.
