Engagement entails much more than rote repetition of a procedure. Math worksheets tend to present very similar problem types over and over, leading to mundane practice of disassociated skills. For students who understand the material and successfully complete an assignment, another worksheet becomes meaningless. On the other hand, for the students who don't understand the material, an alternative method of instruction is what's needed. Another worksheet simply adds to the student's frustration, or worse, contributes to a belief that "I'll never understand math." A cute image or a "fill_in_the_blanks" riddle does nothing to increase engagement or learning (and let's face it, those riddles are not funny!). Instead, teachers need to increase engagement by providing students with exercises in which they discover patterns and relationships, solve problems, or think creatively about math relationships.
The present generation seems to be blessed immensely with intellect and the benefits of mastering math are something worth considering. It is a well_known fact that math is not a subject that one learns by simply reading the problems and its solutions. In order to master the subject, earnest practice on multiple problems is the best way to go. However, not every person is bestowed with required materials like math worksheets to receive adequate amount of practice.