Students can certainly benefit from practicing new skills and concepts on paper. From letters and numbers to report summary formats, worksheets can provide students with a framework for practice _ an avenue for synthesizing new information in their brains. Well designed worksheets can also give students a platform for expressing creative ideas and reaching towards higher levels of thinking.
In 1986, mimeograph machines were (for the most part) replaced by digital copiers in elementary schools. Those of us teachers who experienced using mimeograph machines will forever remember the distinct smell of the still_damp, purple_ink worksheets that we handed out to our students _ by the ream full. (If you're like me, you can remember that smell right now!)