Agreed! In fact it would also be useful in Node: you could build an almost-full-performance but portable version of a native module as a fallback for clients who don't have the requisite software to build a Neon library (say, one they only indirectly depend on) on their machine.
The possibilities of rustc (which has an LLVM backend) and Emscripten (which consumes LLVM IR) are really interesting.