Even more reason to question it?
Someone has to pay for this...
There was an interview on Classic Business years ago when they just started the fuel rewards (I think). It seems like the classicfm archive is not public, which is a pity, but there's some hint of it here:
https://www.ebucks.com/web/eBucks/aboutus/pressreleases/2013/201203rewardtrends.jsp
As far as I can remember, she (the CEO of eBucks) was pressed to explain how this can possibly be profitable for FNB and eventually said that they certainly do make a loss on some individuals, but they look at lots of other things for the program as a whole. The most obvious example would be one of the people on this thread walking around telling friends that he bought a TV with eBucks. That's marketing backed with loyalty. I have no idea what that would be worth, but the point is that you need to be on the other side to understand how this benefits FNB and that it's probably horridly complicated.
My view is that I am clearly getting a benefit here (or being very convincingly fooled to think that I am) and that's all that matters for me. Maybe it's a bit like the uncapped ADSL model where "abusers" are getting way more than the subsidisers and everyone ends up happy, more or less.