Hi Matthew, thanks for the thoughtful idea!
That’s exactly the kind of thing I’m hoping we’ll be able to do 
You can teach both financial literacy and data analysis and some light programming skills at the same time. Imagine a child arguing for a larger allowance because they keep track of their expenses and can prove that they aren’t just spending their money on candy!
During this alpha test we can’t hand out cards to under 18 y/o kids but some form of sub-accounts for family members etc are definitely something we’d like to do in the future Or perhaps something somebody could build on top of our API. In fact, once we allow minors to use cards, the entire program you described could even be developed by a third party on top of our API!