As further assurance, when you go to cancel the placeholder flight in order to use the funds for a preferable flight, AS is very clear on how the funds will be returned to you, and what amount will be refunded. If the indication is that the funds will not be returned to your wallet, you can simply just exchange the value of the ticket for a new ticket, which is slightly more work but much. However, I’ve always been able to have the funds returned to my wallet with a new expiration date. From AS’ point of view, I’m sure they’d rather have you happily buy the ticket and fly rather than reconsider.