It's a standard Visa Cash Rewards card, with the rewards automatically going to the Singularity Institute instead of to you.
After significant research several years ago, I switched to a credit card which has the same percentage values, just provided as cash to me. This was after doing a diligent search of credit card rewards programs and finding the one most compatible with my personal interests (not flight points, etc.). Since the percentages are the same across card providers, I'm thinking it's generally a good deal.
The funny thing I liked to do with the card was to donate to SingInst - after donating, I get 1% cash back on the donation, which I then donate later. If I used this one, it would simply be increasing the amount of donation by 1% without the paperwork in between.
Here's a good article on choosing a credit card from Get Rich Slowly which notes that it is just a tool, and that the interest rates, penalties, fees, and everything else should be taken into account before signing up. From that article, it looks like you might be able to earn slightly more cash back if you have a Schwab Brokerage account or a Costco membership.
One advantage of the affinity card is that it makes use of human psychology to make philanthropy easier for human beings.
Luke posted about this on SIAI blog. Essentially, you can get a credit card with cash-back rewards program that automatically donates money to Singularity Institute.
This seems to me like a dream come true. Am I missing something? Are there any catches? Is there a better rewards program, which I can use to save more money, so I can donate more money to SIAI?