All it means is that the Piston is not the Steam Box that Valve plans to release.

FORBES: Xi3 Is Committed to Piston, While Valve's Steam Box Remains Elusive

Codenamed "Piston", the prototype, developed by Xi3 Corporation and funded by Valve, was unveiled at the CES trade show in Las Vegas.

BBC: Steam 'game console' hardware debuted at CES