Since neither missionaries nor mission boards know what they're dong, unqualified people are routinely sent to the mission field. What missionaries often don't realize is that God works in certain ways, at certain times, in certain places.
Here in Mexico, I have asked missionaries to teach a children's Bible lesson for me, as I cannot learn Spanish. One missionary, who did an outstanding job, complied one time. Others have told me that God didn't call them to work with children. So those missionaries go home empty-handed, while people who are teaching children's classes are getting something done.
Children's ministries do not carry a lot of status. But if God is making a children's ministry successful, His servants will be blessed if they work in it.