Excuse my ignorance, but I've read all the comments and I still don't quite understand what this is good for.

I get that GPUs are a bad fit for many problems, but how fast can this thing be if it has no local cache? Will this really be faster than a high-powered Xeon, or will it just consume less energy per operation? Is it a teaching tool? A tech demo? Something that makes Erlang/Haskell magically run much faster?