Rewards points is today's version of S&H Green Stamps of the 60's. The 1200 stamp booklet was worth about $1.20 (about a tenth a penny a stamp) and redeemed for merchandise.
The very nature of maximizing your rewards points is a game with every credit card provider to get you to use their card and/or link it to various merchants. The rewards vary from 1% to 5% depending on merchandise category, activation, dates, and even volume of purchases (bonus points). The newest "5% war" by the credit card companies shows the vary nature of intense competition.
The economist in me says that this is another indication of inflation. This "rebate" will be captured in either customer fees, interest rates, or passed on to the merchants who will raise prices to cover the merchant fees.
Who are the winners and losers? Those who pay attention to category bonuses, incentives, and pay the card balance monthly will win. The losers are those who carry balances, pay in cash (where no discount is provided), or use a single credit card.
So the general rule of points still applies. Each point (assuming a point is $1 of purchase) is worth a penny to five cents. Now the average American (as of 2009) has about $50K in spending per year with 60% that own their own home and their average credit card debt (2010) is $5K. So.....if you put 80% of your spending on a credit card and get an average 2% back - that is worth $800 per year in rewards points.
PS - For the obsessed Statistician who wants to know every statistic go to www.creditcards.com.