That's all true, and probably a better system overall, but burning an optical disk, labelling it, and putting it on a shelf does feel like a more accessible backup regime for many people. :-)
(Another reason is that the disks do bit rot however, and you'll never know until it's too late. Meanwhile, my ZFS fileserver sends me a email every weekend that it's scrubbed all the disks and found no errors - this warms my heart :) )