For sure, when Cardano realizes it’s full potential you should be able to run a online shop on the platform using the tools that come with the rollouts the develpers are refining, smart contracts will be very useful for online shops, it just gets very technical when combatting the likes of Amazon, how should someone write a smart contract to protect thier business? How do you protect the consumer? How does that contract get integrated into the protocol?
There is a useful tool out now that merchants can utilize that you might like to read about
Cardano Foundation and COTI to offer an ada payment processing solution for merchants
Merchants probably should use this tool 
until some well-defined experts on the Cardano protocol widely accept the style of proposed smart contracts being proposed to be used by our community that want to use smart contracts that allow merchants to move forward with little to no risk.
Remember: Cardano is in its infancy and we all are now the very roots of its future growth, when we lend our self to the protocol and its development we have a chance to build it up and it will absorb that,Cardano does not does not a turn a blind eye to innovation, so if you have idea’s - - - let them loose… 