WASM can be faster than JS but you need a language that doesn't shoehorn a GC into the compiled binary. I'm not really sure what the author expected here. Modern managed runtimes usually give you the benefit of bump allocation in the nursery for free with a generational GC and the runtime has a lot more room to optimize the GC phase. None of this is possible without a native GC for webassembly.
This isn't WebAssembly being slow the benchmarks just show the overhead of the GC. If you are writing a computationally expensive algorithm in Rust or C++ wasm can be a lot faster but its hard to get close to native performance(i.e. running on bare metal x86/arm).
Our webassembly prototype is about 3-4x faster in raw computation(and that is targeting webassembly exclusively) but has a much higher overhead when interacting with the DOM. That is basically the limiting factor especially on mobile.
This isn't WebAssembly being slow the benchmarks just show the overhead of the GC. If you are writing a computationally expensive algorithm in Rust or C++ wasm can be a lot faster but its hard to get close to native performance(i.e. running on bare metal x86/arm).
Our webassembly prototype is about 3-4x faster in raw computation(and that is targeting webassembly exclusively) but has a much higher overhead when interacting with the DOM. That is basically the limiting factor especially on mobile.