Damn.. Ebay must be hurting for businesses.. They sure are giving out coupons on a frequent basis nowadays.. Guess most sellers bailed..
ebay's quarter ends at the end of june. it might be that they are missing their target, and are trying to encourage more transactions.
the problem is that a deal like this effects sales in two ways. it certainly does cause some transactions to happen that would not have happened otherwise, but it is likely that a substantial number of them were going to happen anyway, they have just been "pulled forward", costing them sales later. this causes sales in the following weeks to be leaner, causing them to offer more deals . . . . good for us, i suppose.
i think that this is also why they offer deals exclusively for the app. they are trying to encourage people to use the app over the web site. i am not sure if they report the percentage of transactions through the app and through the web site. it might also be that using the app makes it harder to comparison shop (dont have another window open on amazon, making it easy to compare prices), increasing sales.
i am sure that a big company like ebay knows exactly what effect these things have, though.