The issue is that people cycle despite the conditions and pavement cycling is illegal in some countries (UK). Also pavement cycling is slow and tedious compared to on-road cycling or within a dedicated cycle track.

The idea of making a cycle route "child proof" is not to appeal to current cyclists, but to persuade people that want to cycle but feel the roads are just to dangerous to share them with buses, to get on a bike.

Taking Bath, UK as an example, the river to the west of Bath has a shared use traffic free child friendly path that connects that area to the heart of the city with 12% of people cycling to work. A similar area without that connection on the east side is about 5% http://datashine.org.uk/#table=QS701EW&col=QS701EW0010&ramp=...

This is all about persuading parents that it is safe to let their kids cycle to school as the roads are designed to accommodate that should a child fall off his bike they won't be killed by a car running them over. With that type of infrastructure in place you get a massive uptake.