What if I want to take notes but not contribute to deforestation and issues with the environmental impact of using paper in 2019?
Where are you buying your paper? For example European paper is made from local wood, (re)planted in a sustainable way; also recyling. If you rely on extra cheap paper made from Brazilian wood that might be an argument. The stronger argument is that paper production is fairly energy and water-intensive. That said, I would be highly skeptical that an ipad + pencil is more eco-friendly to produce than however much paper…
The people using paper probably also have the iPad, so it's probably whether the pencil used is more eco-friendly than the extra disposable plastic pens (which it might be)? Then you'd need to look at product lifetime, which is probably more limited by time-passed for Apple users and products than by actual hours of use??
I think these things are always more complex to analyse than it first appears.