* Paper isn't searchable. Say whatever you want about how it lets you clear your mind, but what use is all this information you're taking down if you can't easily locate it later?
* Paper media doesn't have adblock. If you want to talk about distraction...
* Paper media can't be reformatted to make the fine print less fine, or to fix an awful font choice or layout, etc.
* Paper is a pain to handle. Any serious amount of writing is going to require desks, filing cabinets, and so forth, more physical stuff to organize other physical stuff, when an entire lifetime of plaintext notes could fit on a MicroSD card of modest capacity.
* Paper isn't safe. The aforementioned MicroSD card can be trivially backed up an indefinite number of times and rendered immune to fire, theft, kids, angry exes, acts of God, acts of Cthulu, and pets. And not to mention, encryption. While you can, technically, RSA encrypt your paperwork by hand[1], it's almost certainly not an efficient use of your time.
I've no doubt that these hard copy systems work for the people that say it works, but I can't help but imagine there's a certain irrational rejection of technology happening, borne out of a refusal to leave the comfort zone when even something ridiculously easy like Simplenote or Notational Velocity would provide actual efficiency gains.