Hey, go build your app store and sell your apps...until you do no...your not a merchant...your a supplier. Google App store is the merchant.
You seem to not understand your role here. You are not the making the sale. Google is. You simply getting your book/album/software distributed by a merchant.
Does that mean that people who sell apps on Amazon or eBay aren't merchants either?
You're the one who seems not to understand. The middle man doesn't matter. If I am making a transaction with a customer, I am a merchant.