If ScummVM is launched from a desktop environment icon from, e.g. Gnome or KDE, and is started without a terminal errors and warnings are still printed to stderr and are therefore not seen by the user. e.g. Try to start a game from the game choose when the game's directory is not mounted. The game chooser window closes and ScummVM exits - the warning "Game directory does not exist" isn't seen by the user as it's printed to stderr.
Renaming & moving to feature requests