Does footwear have a good or bad effect on children's feet?

Depends: Before a child develops a normal heel-toe motion in walking, shoes are primarily worn to protect from injury. Keep in mind that infants/toddlers have cartilage which is very influenced and it is recommended that they stay in socks and/or go barefoot. You want them to learn to grip. Shoes either have straight or curved last soles, avoid the curved last ones to avoid influencing development.