The user may want some degree of aesthetic control over the artifact.
Users get a sense of ownership and control over an artifact by modifying it.
The user probably doesn't want to have to reconstruct their preferences every time they start a new session with the artifact. Provide a place or working surface where users can pick their own settings for things like language, fonts, icons, color schemes, and use of sound. Allow users to save those preferences, so that they don't have to spend time setting them up again, but do this per user if multiple people will use it. Build the artifact itself to support such preferences. There's a lot to be said about assistive technologies, particularly as they relate to computer artifacts, but space is short.