"Those that want them can use this. Those that don't can hand their devices to their kids."
You're phrasing that like it's an optional parental control feature. But it's not, it's a global requirement for someone's data to be given to the corporation/govt - the choice for a kid user in your example is "parent's data or kid's data". The choice for an adult user is non-existent, they must comply. And yeah ZKPs mitigate the amount of data but it's a different proposition from your statement