"Erm... PSA: Rust isn't the only language that is compiling to WASM."

No, but Rust will still be sitting in a sweet spot, having many of those characteristics I named. For instance, Python compiling to WASM may be useful, but it won't have any of those advantages. Python running on WASM isn't hardly a threat to JS at all, because it won't do anything JS can't. Rust will conceivably be able to in the near term, and as I said, if it takes off and the browsers start adapting to statically-typed functions running in WASM the gap could open even more.

IIRC wasm has no GC capabilities, so Python is an unlikely source language.

In cases like that, you also compile the Python GC to wasm and use it. It ships with your app, adding bloat to your binary though. It does work!

Ah gotcha, have also been pretty impressed by pypyjs http://pypyjs.org/

> Erm... PSA: Rust isn't the only language that is compiling to WASM.

How many other languages are you expecting that most people really want to use but don't require a multi-megabyte VM?