I've got it here in Aus and it's great. The best thing about it is you just tell the people and they get on with it no questions asked.
Had it since launch in SA and although definitely worth it, I always dreaded paying the bill as it was a 20 minute process to explain what the book/card/app was to the waiter, what it entitled you to, then they had to call the manager, the manager then had to either call the owner because they never knew about it or they had to um and ahhh about how to pass the discount through their till. Even had a couple of cases of having to fight with restaurant owners because their coupons appeared in the book but they said they requested removal.