It means that finding the right fit of media (TV/Screen time) for your child should come down to balancing the developmental level and interests of your Child, the Context and the Content.
Allowing your child to watch a show like Word World can be educational if they find it interesting and they watch it as a supplement but not a replacement for hands-on learning.
One of my favorite shows is Word World because everything is drawn in a way that spells out the words and each episode is around one concept.
For example in one episode the duck finds his “relative” a truck because the words rhyme. It calls attention to the sounds in the words while the duck tries to get the truck to swim.