WithoutWeakness :
Intel's NUC and Gigabyte's BRIX, alongside many other designs, are in a similar or smaller form factor to the Piston machine. There absolutely is a market for machines this small. I plan on buying a NUC or BRIX to hook up to my TV in my living room once Valve introduces the streaming feature to Steam and SteamOS. The small 4"x4" footprint in my media console is worth the extra money to me even when compared to small mITX enclosures. I know that the smaller form factor sacrifices some of the ability to use off-the-shelf parts to upgrade it in the future but for a stream-only device I don't need room to put in a dedicated Radeon or GeForce card. Intel's on-die Haswell HD graphics are more than enough for LAN streaming. Buying the right device will serve me well for years without needing an upgrade.
I understand having a cheap/low-power PC for streaming, planning on getting one myself.
I take issue with the Piston specifically because there's a lot of misleading advertising around it, and the fact that it costs $1000. It very clearly advertises itself as a "powerful gaming machine" on their website:
Displays x 3:
With native triple monitor support, the PISTON Console gaming computer offers a truly immersive experience. Surround yourself with vivid visuals supported by 384 graphics cores that deliver stunningly smooth gameplay and uninterrupted gaming action.
If 384 VILW4 shaders can provide smooth triple-monitor gameplay on modern titles, I'll eat my own hat.
There's an emphasis on modularity, but no meaningful upgrades can be made to the components that
are user-servicable (8GB RAM, 128GB SSD, I/O), and the only external module they have is a 1TB HDD. There's also the claim that it somehow uses 10% of the power of a similarly equipped PC, which IMO is complete bollocks.
I'm only mad because I've had a couple friends who almost gave into the marketing hype.