Sounds interesting...
Why does a credit/debit card have to be linked though?
I'm not sure. Like I said, I don't have a "smartphone" to try it with. If it requires it BEFORE you ever do anything, I'd not use it.
If it only requires it for getting more points AFTER you've bought something, then I'd go ahead and use it, but never tell it I purchased anything to get more points. You might lose out on some points, but hey.