First, using counters and other statistical gathering tools, you know how many people are seeing your work, and even where and when they are looking, and for how long they look and read. If you have only a few visits a day, you know you need to figure out better ways to get your work 'out there.' If you have hundreds or thousands of visitors, and no one buys, you know you may have a problem with the work itself, or with the price. Either way, this is valuable information you never get from dropping things off at a store, where your work may not be displayed well, or perhaps the store is just not a busy place.
Second, and even better, selling on the internet brings comments, suggestions, ideas: Inspiration. Some of my very best ideas have sprung from a comment or question. How valuable is that? Extremely, and, once again, you just don't get that through a store.
Finally, and perhaps sweetest of all, are all the people who take the time to simply email and compliment your work. What a pleasure to wake and, with the first cup of morning coffee, read several emails from people who simply had to write and say how they love what you have done, how one day they hope to own something, how something impressed them so much. This past Winter, many a cold, wet, dreary morning has been brightened for me by such emails. You don't get that by dropping your work off at store.
So internet appreciation ~ Yes!