I don't think it was a very effective sandbox at the time Java applets were being used, meaning there were bugs and other glaring security issues. Wasm has the

I don't think it was a very effective sandbox at the time Java applets were being used, meaning there were bugs and other glaring security issues. Wasm has the same sandboxing as javascript, which is pretty well worn in and not slow for the user (partly because of faster hardware now). It's not simply a repeat of java in the browser, or the RCE exploit that was flash.