Well the 200 shows up in your point balance. You then have to order it in the form of a card which will then expire a year from inception (I'm pretty sure, someone correct me if i'm wrong)....but if you want to keep those 200 points in your reward balance you can for a few years anyway before you transfer them to a card. It will say on your statement when your rewards expire in your account.
There are $200 gift card offers and $200 rewards credit offers so it depends which one you applied for. Rewards in your account expire 5 years from the month they were earned (shows on your statement). Gift cards have no expire date.