Could anyone with experience in the area comment on wether or not it's worthwhile pursuing an idea which can only really be monetized in this fashion?
But if you can produce a significantly higher conversion rate by integrating the affiliate links into your core product then it may be able to generate you more income.
You can get the affiliate payment rates fairly easily from someone like Amazon of an affiliate network like CJ so use them to make a spreadsheet and figure out the kind of traffic and conversion rates you'd need to make a viable startup.
If you're trying to sell low margin items like books, and even electronics, it's not sustainable at all. Not even close. Just do back of napkin math and you'll see...
In whatever apps you are building, consider who uses it and what is most inline to advertise, do direct to them. The return is definitely more than what affiliate links will bring you.