One out of every two adults is overweight in the United States. It is way up from five years ago. My babysitter was feeding crackers to my ten-month infant son. I didn't think so. Certainly it is not very nutritious.
Some crackers dissolve quickly in a child's mouth.
Rice cakes are the safest. A greater problem is getting the child used to the cracker type food. Kids get hooked on crackers at an early age because they are high in salt and fat and are easy to eat on the run. A child will reject a more nutritious food when it is introduced because the crackers make the child full. Please avoid peanut butter until a child is much older and even then try to limit it to no more than once a week at the most.