It's basically a PC, which runs Windows software, based on all the description and rumour in the article.
Why not just buy a Windows PC?
Seriously. Unless they somehow undercut large hardware manufacturers, it's no different to just buying a gaming PC and plugging it (presumably) into your TV.
It's aimed at the console players (vast majority of gaming) that are, maybe, interested in PC but are also terrified of PC.
Great market to tap into, imo.
Plus, with the various cheap, independent games that are widely available on Steam, it makes for a great family system (great puzzle, interactive, cute, soft games) as well as a target for the mobile/facebook game people.
You limit the number of ports in the back, a closed plug and play system like your your console.
Granted, it will likely have the same issues that PC has--why does this game work like shit with my system? What? You mean it wasn't really designed for my GPU? wtf is that??? Not sure how to get around that, other than making a steam client that is specific for this console and limits you to certain games (terrible idea, right?) OR--refine their customer support and patching system to let steam effectively handle driver upgrades via simple button pushing--I assume it's possible to run software like CCleaner in the background, and system macros hat will automatically uninstall, restart, clean registry, restart, install fresh drivers, restart?
that sort of thing? Pretty much what the PS3 does for system updates.