Because that way they can't ignore the game but are forced to play it more than doing the dailies and then log off. Also likely because they hate having to repeat the quest over and over

To be fair it's likely done because they're done on demand instead of having a certain amount of units done immediately that may never sell. Also because Amazon for Business can go anywhere without having to deal with travel expenses for the merch

Uh. Any particular example you can recall by chance?

Oh trust me, I do and it's on point