Coupon vs Gift certificate

Sorry if I've missed this in the documentation, but can you please explain the difference in function between a gift certificate and a coupon
Thanks

The only difference is in the number of uses.

With coupon, the number you enter in number of uses is treated as the coupon can be used {x} times per user.
With gift certificates, the number you enter in the number of uses is treated as the coupon can be used {x} times total.