- I would rather get a bill on paper than an email saying that I can download said bill somewhere after logging in, re-entering my passwords and sometimes entering another PIN (German o2). Of course there are also companies capable of attaching a PDF file to an email, but these appear to be the exception rather than the rule.
- Tracking expenses by means of little strips of paper could be improved by putting little QR codes on said little strips of paper. You could scan the code, track the expense, drop the paper. But this would require a standard of sorts, and I doubt that it would be easy to implement in the fifty bazillion legacy checkout systems.
- Scientific work (read: calculations) either require paper or blackboards, the former being easier to handle if there are many calculations, the latter better if there are fewer calculations and more thinking. But then you also want to be able to see at least three different pages with four different formulae at the same time. Given that carrying around three iPads is rather unhandy, you’ll either need a book (or two or three) or print out those damn lecture notes.
And if you just printed 150 pages for some calculations, you can hardly complain if you get a few bills each month…