1) this isn't money you earn from Amazon...so they're not creating a closed amusement park style ecosystem where you HAVE to spend the money you make with them

1) this isn't money you earn from Amazon...so they're not creating a closed amusement park style ecosystem where you HAVE to spend the money you make with them 2) you don't have to convert ALL of your cash into Amazon credit. You can allocate a portion that is useful to find cheaper/better selection of products on Amazon. They rest you can spend wherever/whenever you want