Nobody was claiming that WASM would replace JavaScript in general, magically or otherwise. I think there's reason to believe it will replace asm.js since it's already being integrated into Emscripten and the major browsers have already landed support in their stable releases.

I find comparing it to Flash or Java applets weird, given the fact that you clearly understand that it doesn't interact with the outside world using any WASM-specific APIs. Both Flash and Java applets could in theory interact with the outside world only via a JavaScript wrapper but that was never the use case they were aimed towards either in theory or practice. Flash and Java applets also used languages that map much better to JavaScript's execution and memory models than C/C++ do, so the APIs were a big part of what you were getting by going that route (especially in Flash's case, where you had to learn a totally different programming language just for Flash).

Unless you consider people who using things like Node.js or Electron to be "insecure about touching C/C++" I don't see where you get off saying that about people who want to use WASM. Sometimes you have existing code or expertise in a certain language, or it simply fits your problem better.