Nick summed it up pretty well and I'll input my thoughts.
Henry, years ago I had this great concept to clone the App Store from Snow Leopard and unfortunately, a dedicated "Leopard Market" was just not a very good idea to spend time developing. My idea was a full on program where the only thing it would source from the internet was an App to download, however that made many things a possible inconvenience to the user and me being the developer.
Going web based is a much better idea as content can be added/modified/or deleted on the fly without having to release a new 40MB update for Leopard Market. The website idea was a much better approach and that is why I never pursued developing Leopard Market.
However, if you do decide to continue working on your program, feel free, nobody is going to stop you. It was just not the right option for what I planned to do.