The ability to use a stylus or pen has always been a favorite feature of mine since Samsung released the Galaxy Note line of devices. With the Chromebook Plus/Pro release you could see that Chrome OS was setting the stage for the stylus support going forward. My go-to application for sketching and jotting down ideas has always been Google Keep. With core features centering around note-taking it could never be more than an organizer and to-do list creator.
You could always go the Android route and download one of many drawing apps from the Play Store but I always want something designed with Chromebooks in mind.
I noticed the Canvas app after a recent update to my Chromebook Plus. It works great on the Pixel Slate as well but will work in any Chrome browser. For anyone who wants to try it out go to the canvas.apps.chrome in your Chrome browser.