The real goal is not proving anything to in-laws, it is keeping a heritage kid's handwriting alive. A small daily from-memory habit does that, and the proof takes care of itself.
Paper Chinese workbooks need a parent to grade them. Here is how an app that checks stroke order automatically saves busy bilingual parents time and frustration.
For school-age children, an interactive app can do what tracing books cannot: hide the character and check recall. Here is when to make the switch, and when paper still wins.