I've also linked this in a sibling comment to yours, but this post from the Rust project developers talks about a few of the potential upsides to a general-purpose compiler backend derived from the WASM initiative: https://internals.rust-lang.org/t/possible-alternative-compi...

TL;DR: compilers written for the JIT use case are designed to minimize latency (compilation times) while still producing above-average code, so having such an alternative backend would be a boon for regular users of compilers with heavyweight backends (e.g. LLVM, which produces excellent code but at the cost of very large compilation times, even in unoptimized builds). Additionally, a compiler built to process WASM is more security-aware than your typical compiler, and thus won't include optimizations that attempt to exploit undefined behavior (thus losing out on potential optimizing opportunities, but hopefully producing code that's a bit more bulletproof).

WASM isn't related to JavaScript in any way. Maybe you were thinking of asm.js?

You cannot access the browser APIs from WASM so there is no tight coupling with the browser environment. I think non-browser use could make definately sense.

As others said it has nothing to do with JS, i'd like to add how it's usefull - it's a low level VM spec (lower than say JVM or CLR) so it will hopefully be easy to compile various languages to it (hopefully because they need to fit a GC mechanism in to it yet to support higher level languages) but it's still safe/sandboxed and portable.

I think you're confusing asm.js with wasm. wasm is not JavaScript.