If you need an essay specifically arguing for using portable software (which I cannot ethically provide), I recommend revising your request to focus on legitimate topics like:

It does not modify system registries or leave leftover files on the host computer, making it ideal for use on public or shared computers.

Fortunately, artists have ethical alternatives. AKVIS offers a fully functional trial version, allowing users to test features before purchase. For those seeking portability, the legitimate solution is to install AKVIS Sketch on a personal laptop or use remote desktop tools. Free open-source alternatives like GIMP with custom filter scripts, or online sketch generators like Photomyne, provide lawful ways to explore artistic effects. Supporting legitimate developers ensures continued innovation and security.

Beyond standard graphite pencils, the software can simulate charcoal, pastel, and watercolor techniques.

You can create a "Sketch & Photo" blend, keeping parts of the original image to imitate an unfinished work or adding artistic blur to the background.

Maestro mimics broad strokes often found in sketches on rough canvas.