It absolutely will. I've compiled like 30 projects to the web now and across the board I'm seeing 10x to 40x improvements in speed compared to idiomatic JavaScript. Here's one of the Benchmarks I ran:

Native: 57.26 ms

wasm Firefox: 143.35 ms

asm.js Firefox: 162.43 ms

asm.js Edge: 199.70 ms

wasm Chrome: 223.80 ms

asm.js Chrome: 268.60 ms

JS Chrome: 2898.20 ms

JS Edge: 3240.00 ms

JS Firefox: 5558.88 ms