وَمَا خَلَقْنَا السَّمَاءَ وَالْأَرْضَ وَمَا بَيْنَهُمَا لَاعِبِينَ
We did not create the heavens, the earth and what lies between them as a game.
لَاعِبِينَ excludes the notion that creation was frivolous. The qualifier addresses a particular misapprehension about the purpose or character of the act.
The addition need not mean merely a smaller set of acts is selected. Its rhetorical force is to reject a potentially imagined description; not every qualifier is only a device of class restriction.