Plus, Monaco powers more than just Visual Studio Code. Visual Studio Team Services and the Azure portal uses Monaco as editor of choice in a large number of places. Monaco powers online REPL/sandboxes such as Typescript's playground [1]. IE10+ and Edge Dev Tools are powered by Monaco (and the minimized gunk of the average random webpage sources was an early impetus for Monaco to have much of the performance we see in VS Code today).
[1] https://www.typescriptlang.org/play/index.html