[mckravchyk]

It's a wrong comparison. A high-level language is usually good enough for a desktop app because there's not much ongoing computation happening. It's only input processing and small, infrequent updates to the view in response to the input (not to mention rendering of the DOM and low level input processing is done by the browser's C++ compiled code). A video game on the other hand has to do computations all the time at a very high frequency.