What is the reason for making a JavaScript runtime based on browser APIs that cannot also be a browser? Or in other words, wouldn't it have been easier and bet

What is the reason for making a JavaScript runtime based on browser APIs that cannot also be a browser? Or in other words, wouldn't it have been easier and better to make an optionally headless version of the Servo browser with additional native APIs and some enhancements like being able to run JavaScript directly in addition to HTML? The choice made means that Deno can't be used, at least directly, to make desktop applications, and also doesn't have all the features that browsers have for free, like multiprocess and multiple sandboxes, network traffic inspector, local storage, GPU compute, etc.