Here is the best summary of the pros and cons of the ‘Thank You’ Rewards Program from Citibank:
Pros: Earning miles is very quick. If you travel a lot internationally, you can earn with one example of 1,000 “purchase points” for buying the ticket on aPremierPass card (with Thank You points), and an enormous 10,000 “flight points” for the actual miles flown. That’s 11,000 points in one transaction. In this example this person racked up 52,000 points and spent only $3,000 on the card! With the good news comes the bad news…
Cons: You can only spend flight points and purchase points in equal amounts per transaction. In other words, having lots of flight points doesn’t mean that much when it comes to redemption unless you have the purchase points to support them. A person with 18,000 purchase points (including a 15,000 signup bonus and $3,000 spend with the Citi PremierPass Card), you may only use the 18,000 purchase points and another 18,000 flight points right now. Since flight points rack up much faster than purchase points, you will always be tied down by the purchase points! You are told this in the fineprint, but you will not see Citibank’s Thank You Network advertising it clearly or it would run people off to a better program. We also read that Capital One has a similar program that people have been complaining about in their blogs and travel forums.