I fully confess I, personally, am unlikely to need this tool, but there are instances where people won't have access to digital dice rollers, have spiritual reasons for not using tarot or face cards, or may be under some kind of imprisonment (jail, psych ward, etc) where certain tools are restricted.
This document is written for brevity, which I appreciate, but honestly I think it would be nice to see it expanded and more bluntly explained.
(I'm saying it's good, I just want more.)