For some people this is settled by drawing in the margins of a piece of paper while in class or during a meeting. For others it's with the camera in their phones. While that's admirable, it's not serious. You have to commit to whatever it is you choose as your visual art. That's where these tools come into play.
If you need help understanding the basics of the Pen Tool, download my free poster! It's perfect for display in a computer lab, a classroom, in your office, or anywhere you might need reference for the Pen Tool.
Not to get metaphysical here, but erasing is more than just s simple action to an artist. This may sound like bull, but especially to a budding artist, there is a lot of implication to the simple action of erasing a mark from your paper.