• Probably cheap as dirt.
• Entertains very small kids who are statistically going to be the loudest, most impatient ones.
• Engaging for those small kids neurodevelopmentally.
• Hard to damage.
• Not ingestible; hard to otherwise hurt yourself or others with it.
• Can put it basically wherever and even screw it down onto a table.
• Too big for someone (especially a kid) to steal.
• Very quiet even if you’re playing very aggressively with it.
• Cross-cultural (e.g. no language involved).
• Not consumable like crayons.

It’s got too many things going for it.