I have two favorite quotes from Pamela Livingston's excellent book, 1-to-1 Learning: Laptop Programs That Work. Here's the first one:

If it takes 40 minutes for an environmental science class to gather weather data from atlases and almanacs and turn it into pencil and paper charts, how much time is left to think about what the chart is saying? How much time is there to consider "what if" scenarios, such as, "What if the mean temperature rose by ten degrees?" Equipped with a laptop computer, access to the Internet, and a spreadsheet/graphing program, however, students can quickly find and analyze current data. They can plug that data into spreadsheet templates and prepare charts for half a dozen different "what if" scenarios in the same amount of time it would take to make a pencil and paper chart. [Laptops] allow students to get to the thinking faster. [emphasis added]

We waste so much time in school doing things on paper that are more efficient on the computer. One of the primary reasons that adults use computers instead of paper is enhanced productivity. What could teachers do with all of the time that we'd free up if schools made a significant shift away from paper and pencil?

If you haven't checked out Pamela's book, it's well worth the read!