[GeoffR]

It looks like a good idea, but will depend a bit on the details.

If I normally need to spend $10 to get 100 superpoints, and the first book I looked at normally costs about $10 and needed 6200 superpoints to buy, then it is really a very small reward indeed, but as long as it is in addition to the normal discounts and promo codes then it will still be worthwhile.

Important for me is that there seem to be plenty of eligible books from the big publishers, it is not limited to the usual lists of heavily-promoted self-published books.

Edit: Also noticed that books by Hachette earn superpoints too, a publisher that normally never allows any sort of retailer discount whatsoever.