I am sure they are collecting purchase data (but honestly, who isn't these days?), while some of the promos they offer are for new products, so that may be some of the incentive as well. They also earn commissions on items purchased through the app and website, as well as inactive fees (deducted...
I mentioned this very briefly on the podcast, but a great money-back service I've been using for the past year has netted me over $150 at the grocery store and online, offering nearly instant "cash back" on items you purchase. For example, I purchased my new TV from Best Buy using a link from...