1) Your wares are available for viewing 24 hours a day, not only when your shop is open.
2) You save money. Think about it. Selling in a shop, you pay rent, utilities and employees. Selling online, you pay minimal fees.
3) You reach a wider audience. People from all over the world will see your items, whereas, selling in a shop, only local people who take the time to come to your shop will see your items.
4) Cheaper advertising. There are tons of ways to market your online shop and direct traffic to your shop...most of them for free, many of them for little money.
5) No need to pay extra fees for accepting credit card or debit card payments. PayPal, Google Checkout and Amazon Payments take care of all that for you. Sure, you pay a fee for this service, but it is so convenient!
6) Greater support. Most online shop venues offer support for sellers and many sellers group together to support each other. In a physical shop, it is you and you alone. Maybe a little support online from the Small Business Association, but not as strong as in an online shop.
7) Multiple shops. You can have different locations in different venues. You can sell on Etsy, Artfire, 1000Markets, ShopHandmade, Dawanda, as well as many other online options. Having multiple physical shops is out of reach for many business owners.
8) Ease in transactions. Electronic transactions with online shops make things easier. You don't have to nurse your cash register all day. In fact, wait for all your orders to come in and fill them all and ship them all the next day at the same time.
9) Personalization of packages. It would be ludicrous to decorate fancy packages while your customer is standing right there impatiently waiting for you to hand the bag over while you draw a picture in gratitude. With selling online, you can wrap the item, wrap it with ribbon and draw pictures on the back of the bubble envelope. Many buyers like to see sellers take that extra step.
10) Limited need to collect sales tax. You only have to collect sales tax from customers in your own state. An advantage for the seller in making your taxes less complicated and an advantage for the buyer in saving a percentage on their purchase.