With Linux the entire operating system with MyPaint or The GIMP installed is available for booting and running if the bios are compatible on different computers.
Open source software offers so much more freedom.   You can run programs like The GIMP and MyPaint on any Linux operating system along with Macs and Windows.   Open source software most often will install on a USB thumb drive providing portability of using on different computers with the same Windows operating system.    With Linux the entire operating system with MyPaint or The GIMP installed is available for booting and running if the bios are compatible on different computers.    Most commercial software offers less freedom allowing use on one system and possible a second as back up, most will not install on thumb drives for portability.