From another thread:
I do not believe this will be at all useful for mining. 16 processors at 700MHz each = roughly the same as 4 processors at 2800MHz (2.8GHz) which is any modern PC CPU.
So would you be excited about a new quad core CPU running at 2.8GHz from Intel or AMD? I certainly would not be.
So it's just as useful as CPU mining. If that gets you excited, go for it.