Look cool, but I was envisioning a more general approach I suppose, not limited to a single specific language/tool. Flutter still outputs a x.js which is interpreted by V8 and runs within the Chrome sandbox, what I meant was more along the line of a supercharged browser able to run e.g. the JRE allowing to run any random java program out there, but then accessed over an URL and requiring no manual "installation"/copying/extracting files or interpreter setup. Same for e.g. a native Dart app. So you would be able to run any native application (given it's built for your platform obviously) within this kind of browser, you could run chrome in it and access the web like usual I suppose?
So I guess just hassle-free native apps with a focus on client/server architecture like websites, running gimp/paint doesn't seem like a good fit for something like this :')