Can footwear help or hinder children's foot health?

Depends: If properly fitted and supportive they can help.

Foot health: They can do both. See your podiatrist for help.

Interesting: For children with normal feet, there isn't much evidence that there is anything better than running barefoot (assuming that it's warm enough and there aren't any sharp objects.) normal children don't need special arch supports. Hard soled shoes don't make it easier to walk and probably make it harder. The best advice is to avoid buying shoes that are too small.