The only reason I can imagine is that most use cases require other specific knowledge that will also seem like useless stuff to 99% of the students and its hard

The only reason I can imagine is that most use cases require other specific knowledge that will also seem like useless stuff to 99% of the students and its hard to find a use case that fits most of their probably interests. "So in the future, when you're writing a ray tracer..." just doesn't ring with most students anymore than the word problems that required the formula either.