Not that I think the credit-reporting system in the US is sane or fair, but one of the factors that may go into one's score is the amount of credit you have ava

Not that I think the credit-reporting system in the US is sane or fair, but one of the factors that may go into one's score is the amount of credit you have available to you (i.e. a reflection of how much other lenders have already decided to trust you). So if you have a bunch of credit cards with low balances? That looks good. You can only get approved for a couple, and you push them to the limit constantly? That looks bad. An account closes, for whatever reason? Affects that metric. I wouldn't expect it to be significant, but people who monitor credit closely might notice.