There are still a significant number of people who use only paper copies of their genealogical data. The reasons for doing so, run from a lack of computer knowledge, to comments about being better able to visualize the information on paper. I have long since learned that I do not get into discussions with these people about using computers. It is not productive. I was very early in adopting computers for my genealogy, using an Apple II with a dot matrix printer. It seemed to me that given the amount of information can more than double in each generation, there was really no way to keep track of all those people, dates, places and facts without either using a strict organizational structure or letting a computer do the organizing.
Of course, my Great-grand Mother never had the opportunity to use a computer. Everything she did, she did by hand or by typewriter. As an aside, I was showing one of my grandsons a picture of a typewriter and he didn't know what it was. Back to Great-grandmother and her genealogy. In going through all the work she did for over thirty years, it became apparent that she repeated several of the lines more than once. There were as many as four and five copies of the same material in her files. Even today, with very advanced computers and programs, I still have some duplicates. But, why do I use computers? I could answer like George Mallory, the mountain climber, because it's there. But the real reason is more practical, computers enable me to process the huge number of individuals that make up my database. Our family's genealogical efforts go back several generations and I have inherited a good portion of all the previous work. Quite frankly, without computer assistance, I would never have completed even a first level survey during my lifetime.
Circumstances have given me the option of using some very sophisticated computer hardware and software for the past twenty years or so. On a recent visit to one of my wife's elderly cousins, a former Accredited Genealogist, the cousin showed us some documentation she had accumulated. Because I had my digital camera handy, with her permission, I was able to make high quality copies of the information on the spot. This ability to gather high quality copies of information is a hallmark of the digital age. My present document file contains over 78,000 items, including photos, scans, and documents of every possible description. There is simply no way that I could handle that huge amount of paper. Some of those items have hundreds of pages. My photo archive alone has over 56,000 images.
Let's assume that I wanted to preserve each of those photo images on paper (or other suitable medium) that would be 56,000 pages or 100 volumes of 560 pages each. If I took the photos and put them into archival photo sleeves, it would cost over $46,000 just for the sleeves. (From B& H Photo) You can see why I put a premium on moving information digitally.
Now, back to the paper world. Given a good indexing system, like those used by larger libraries, even a paper system is workable. But you have to put the paper someplace. My entire files can be put on one hard drive about 4 inches square. I can carry my entire database with me where ever I go, if I choose to do so. Given a reason for doing so, I could transfer my whole database of files to another person in a matter of a couple of hours of copy time. (By the way, I give backups of all my files to each of my children periodically).
All of these reasons are why I use computers for genealogy.