Illustration does have a place. I love the pictures by Lynd Ward for Robinson Crusoe. They have a richness for me that is, still today rivaled only by Rembrandt himself. When you are a child, the few things that are your windows on the world are decisive. They fill your mind.
All later impressions have to crowd in, find a place among many impressions.
What a tropical storm might be, I learned forever from the one behind Crusoe with his goat-skin umbrella. No later storm, however wet, will ever match it. What you become acquainted with first as a child is fate. Let it be a good one then. I am not against illustration, but I do think that the superiority of the unillustrated deserves a place.