Hmm. I didn't say it was interpreted in any given browser implementation. I was judging the serialization format for what it is, vs reasonable alternatives. Analysis, transformation and interpretation are what you want out of this kind of encoding.

I also don't agree re expensive validation; I think you're wrong. Interface with APIs much more problematic than pure computation, which is not hard to validate. Interface safety is largely the same problem as with plain JS, as I see it. I don't see stack machine vs register machine making almost any difference at all.