The miles will be easier to use than the companion certificates. I had the US Barclay's card, and cancelled it before the fee was due. Was almost impossible to use the certs (& I'm a PHX US (& now AA thankfully) hub captive). The list of blackout dates listed on the back of the actual "certificates" on the "welcome kit" is obscenely long, and usually includes most holidays except for Arbor Day, Grandparents Day and National Fudgesicle day.