The point, though, is that it is a free (bonus) credit of having stayed one night added to the total nights you've stayed for the year, not a certificate for a free night's stay.

You do get additionally a certificate (e-certificate) every year for one free night stay, the first one (good at a category 1 through 4 property) is given when you're approved for the credit card and the others are given annually about the time your annual fee is due and those are currently good at category 1 through 5 properties.