I remember being told this during my interview prep classes in college in 2008. Interviewing was so much more formal even then (in the NYC area): business casual attire, (p)leather-bound resume folios, expectations of knowing the company, etc. I definitely don't miss any of that nonsense.
I recently showed up to a new startup interview, with a similar folio (with printed copies of my resume, and a tablet of graph paper), and it paid off.
I was in a small conference room with the two co-founders, and of them hadn't seen my resume, and was trying to read it on his phone while we were talking.
Bam. I whipped out printed copies for both of them, from my interview folio.