I'm in law, and it really depends on the kind of practice you run. In some aspects of my practice, I'm completely paperless thanks to my trusty Surface Pro 3. I can mark up and revise documents more easily on the screen than I can on paper using the excellent pen and drawing features. In other areas of practice, we are required by law to mail things to people, so there is no getting around the paper there. Real estate transactions do require a lot of paper, but it's all done in one big pile at the closing; everything up until that point is paperless.
As far as court filings go, the courts have seen the light and are migrating to electronic filing. The big advantage for them is that instead of receiving paper in the mail and having their staff enter all of the information into their computers, they can have the attorneys do all of the data entry work for them when they file electronically.
I am mostly paperless in my personal work, with the consequence that I can work from anywhere as long as I have my laptop with me. However, the one piece of paper that has resisted digitization the most is my to-do list. When I put it on the computer it's too easy to just close the file and ignore it. When it's on paper, it's always there staring me in the face.