This is a nice alternative. Bookmarked! As I'm sure you know as a parent by now, the next nice-to-have feature would be to filter against apps that use ads. Worst offenders being full screen video ads you can't skip and banner ads placed close to buttons.

Children are quite vulnerable to believe what they're seeing in the ad verbatim. Then you're the bad guy for not agreeing to get them that game they just saw beeing so great. More importantly though, brainwashing with ads steals the time that was supposed to be spent on something else.

At least your "No IAP" filter already eliminates the awful apps that let children "earn coins" for watching ads.