WASM is basically a way to deliver the old JVM promise of "compiled once, run everywhere, sandbox if needed", with the additional constraint of "close-to-native performance" and "any language can compile down to it". It's a good thing if it delivers on all those promises. And it's especially a good thing if you don't like JS, because it's our best shot at dethroning JS.
I think Cargo and GoReleaser already make this simple enough. Heck, even Alpine Linux has down the process of compiling for multiple architectures for multiple languages. It really isn't that much of a challenge to do so and there are already sandboxing solutions for each operating system. WASM doesn't get rid of JS, it just puts sandboxing into a JS-based engine. The last thing people should want is to run binary blobs in your browsers which is exactly what it does. The same browsers who gladly trade privacy at ever iteration. Might as well just go publish your browsing history online cause that is where this will lead.
Wasm doesn't get rid of JS in the browsers right away (but long-term I suspect that JS is going to be implemented on top of wasm). Wasm itself is not JS-based tho, as evidenced by all the standalone wasm runtimes.
And it's not any more or less transparent than a minified blob of JS.
Well, one the developers are smart enough to create optimized packages for each architecture but instead if they wanted to cater to bad practice JS fans they could create a universal binary.