I was able to benefit from the $125 credit for 2 years, which actually reduced the price of the ticket by that amount when I bought the ticket and paid the CC bill. Now, it appears you will have to buy 2 different tickets to benefit. The first ticket triggers the Travel Bank credit, then you need to actually buy a second ticket at a later date and hope you can use the Travel Bank, which isn't always offered as a payment source when buying tickets.
I'm cancelling the Quest anyway, as I just got the Club card, but the $125 credit on Quest was a major selling point for that card product. Some of our kids have the Quest card, so will see how they can actually use that Travel Bank credit.
I have Travel Bank credits now from some dopey promo they ran a few months ago, and I have yet to be able to use it for anything.....