The excitement is because Lua is a very nice little language with the explicit goal of being embedded into programs, so when a pure-go port of the language appears that is not just bindings to the C version it is warmly welcomed.

And no, it shouldn't be any faster than luajit (what can really :)

Its just an extension language for go programs, The advantage is that is uses the go garbage collector, and can interop with Go code nicely.