There's no difference--that small JS text file gets compiled on the fly into platform-specific assembly language with today's JIT compilers in browsers. WASM is just skipping the text source step and giving browsers something they can compile directly.

I do agree it is a shame to lose direct insight to the text source code, but let's be honest the production JS shipped to browsers today is far, far from being human readable. It's minified and shrunk to the most small and incomprehensible degree to save bandwidth. View source and try to read and understand the JS on any big site like facebook.com, etc. and you won't get very far.