I don't think this is really attractive for sellers or buyers. Everyone could buy some webspace and set up his own store. Or just rent a webshop with own domain for $9.99/mo, choose background and title and start selling.
Every website that wants to compete against eBay must be dedicated to gaming and must have much better features and options tailored to games. We already have 1 billion websites offering webshops.
I can see your point, and yes someone can get there own webspace and domain, but how do they make the website, what software, payment options, can they intergrate api's, how do they do it, javascript, php, html, html 5, xhtml, css, would it be css and xhtml valid. What would they do about SEO, be someone who barely shows up on google, so they won't sell any products.
What do they do when their website gets hacked? Panic like everyone does.
I've recoverd many hacked websites for people before and charge £250 and why was they hacked? Simple they were poor, created on free software, with holes everywhere.
I'm a web developer and designer, My code for this idea is rock-solid, with lighting quick hosting, they will already have 50,000 people looking from my own website, with me advertising the website, not them, they don't need to pay a penny to advertise it.
With it's own gaming social network also being launched at the same time, it's dedicated to gaming.
it's not simply offering a webshop, it's much more than that, it's the next generation of how games will be sold.