All credit card point earning categories are not created equal. Many credit cards offer bonus points on certain categories such as gas an groceries while purchases at big box stores are often excluded.
My Hilton HHonors American Express offers bonus points at grocery stores. Many grocery stores now sell gift cards for various other places. Since restaurants no longer earn bonus points on that card it can be used to purchase restaurant gift cards so the grocery bonus is earned instead of the standard point rate. It takes some advanced thought and relegates one into chain restaurants, but if you are going to eat at Chilis anyway might as well get some more points with it.
If you are using another card’s portal or one of the various airline shopping malls verify before hand that purchasing gift cards counts. Many times purchases of gift cards or purchases made with gift cards do not count for bonuses.