This is just a rough brainstorming...
From merchant side
1. Merchants can easily add "Pay with bitUSD" button in their websites or blogs.
2. They can easily collect shipping information pertinent to each order (probably combined with mailing function? Memo is too short to implement this)
From customer side
1. Customers can easily convert their local currencies into bitUSD through gateway/exchanges.
2. They even don't have to install Bitshares wallet. Instead, they can use bitUSD on web wallet.
(For 1 and 2, Coinbase is a good example. It allows people to buy BTC and to use on web-based wallet or mobile wallet)
3. Their purchase can be protected by escrow service
4. They can get confirmation email and shipping notice (via mail service?)
ADD: 5. They can figure out the reputation of sellers
My imagination is that everyone can sell and purchase goods and services on their blogs and simple websites with bitUSD instead of big online shopping mall. They don't have to pay a high fee to ebay or amazon, hence this benefits both consumers and sellers.
Please provide any thoughts of yours on this.