Bear in mind that listing a product in your E-junkie Shop is an optional step that's performed separately from simply adding the product in Seller Admin. Most sellers simply want to sell from their own site and never need/want to have an E-junkie Shop page as well, so they only add their products in Seller Admin and obtain the button codes we provide for those to paste into their site, and so they never need to take the extra step of also posting listings for those products in their E-junkie Shop.
If you have an active subscription, products in your E-junkie Shop are also listed in the general E-junkie Marketplace. Our site is not a major shopping destination site like eBay or Amazon, so buyers don't really come to our Marketplace and just browse around looking for things to buy. The Marketplace primarily just provides a way for search engines like Google to find your products, if you don't have a site of your own that they would normally find otherwise.
If you post a product listing with a Demo URL, the product listing would include a Download link to access that demo file. This is entirely unrelated to our digital-delivery feature for paid downloads, which works the same regardless of whether the buyer orders from your site vs. ordering from your Shop. This help page explains our download delivery feature in detail:
Products listed in your own E-junkie Shop would have Add to Cart buttons, so buyers can browse around your Shop and add multiple items to their cart before checkout. When those same product listings are found in the general E-junkie Marketplace, they only show a button that says Buy Now, to avoid giving buyers the mistaken impression that they could add multiple items from various different sellers to the same cart and checkout all of them together at once (each seller's carts have to remain separate due to differing settings for payment, tax, shipping, etc.). However, that type of Buy Now button actually just adds the item to a cart associated with your seller account, so if the buyer proceeds into your own Shop from that product listing, they would be able to add your other products to their cart from there before proceeding to checkout.