It looks to me like you're making the sophisticated point that some facts vary in usefulness. I agree.
The point being made by Gradgrind is much more basic: children should focus on Fact over Fancy. As an example, he refuses to teach his children fairy tales, deciding that they should learn science instead. (Unfortunately, Dickens presents science as dull collections in cabinets, and so the children are rather put out by this.)
Another month has passed and here is a new rationality quotes thread. The usual rules are: