It not exactly like purse.io for people in purse.io would buy the amazon product for you then get the crypto. The person buying the crypto pays a slight more premium price and the person buying the project with crypto gets a discount bc of the high price.
If @paywithsteem become more like this i would use it more.
The other part aka @paywithsteem the one buying the product for someone else in exchange for crypto can stay and charge a higher price bc it a quicker service.