I really really cannot see how this is going to help Waterstones.
In these cash-strapped times, people are much more savvy about shopping around, and I'm sure actual hardware sales won't be significant.
And I can't see ebook sales making a huge leap in cash for them, because not many will buy there, unless they are priced at least the same as Amazon. I don't think the "Store Loyalty" will have much effect - it didn't with me, nor friends who got Sonys from them.
The only way I can see it is as suggested - a fee for every sale from every account opened by Waterstones - but that still means they have to sell the devices originally.
And this wifi in the shops etc.. (all of which will cost capital)to help the digital buying "experience" won't make much - and Waterstones were always well known for their coffee shops and sofas long ago.
No, I'm both mystified and saddened - after all the talk about Amazon being unhelpful for independent bookshops - well I reckon he wn't have to worry anymore now.......