I think most people miss that right now webasm is good for run speed, size, and loading speed, but is not geared nearly as much towards using any language in a web page, since IO needs to be exposed to javascript.
The more other languages I learn, the more often I come back to Ruby. I'm excited to see it becoming a more portable language, and I think it'll make a good language for web clients someday.
If you try to write the web assembly part in ruby, you are sending your users a run time and using an interpreter that is itself being JITed, purely to transform some amounts of data between IO from the user, including any information to and from the DOM.
This is what concerns me a little with WASM. There are already too many web development experiences that prioritise developer experience and neglect user experience, I'm wondering what future we're walking into where we bundle three different standard libraries, ignore binary size, etc etc
To me, it seems that the user experience vs dev experience trade off is subject to market forces and if it swings too wildly in either direction, a competitor will come through and wipe the floor with everyone else, no? It's always seemed unnecessary to me to worry about the effects of _more_ options, at least in the context of application development anyway.
It turns out people like to use the languages/environments they already know.
And there is currently pretty direct access to a canvas.