When you open a new card there's a small hit to your score when they do the hard credit pull but that goes away after a
couple of months and then when you close the card, I mean there could be a hit to your credit score depending if it really affects your
utilization ratio by removing a bunch
of unused credit but probably not and most
of the people doing this, you're talking about people whose credit scores are probably somewhere between 750 and 850.