I can't believe I'm defending Prilepin's Chart. But c'mom, be fair...the fact it does not adapt itself to the way some weightlifters calculate accessory movements does not diminish it's utility in the slightest. It's a rule of thumb.
I'll not prejudge what a person does or does not need to know in order to understand the chart. You're correct that it is a tool, but I disagree that it has limited utility or that you need a huge base of knowledge to get it right. My position generally is that most people already have too much information about training. Most would be better off with a limited set of very basic tools to master so they could over time begin to understand how they respond to intensity and volume.
As to what it takes to utilize the chart, the great irony is that it was developed for weightlifters but I'll bet its greatest impact in recent years is with the crowd that re- popularized it, powerlifters. I do know that it's used extremely widely by adherents of the Westside template with great results. I have also found in watching thousands of sets and reps among training partners, trainees etc...when I observe people at working weight (70-99%) across several sets I consistently see a significant drop in performance right about the rep range limits that the chart predicts. I also note that when using some of the most effective progressions (3x5, Ladders, the 531 method) the working reps correspond with the chart with a fair degree of accuracy.
So, yes, It's just a tool. You might need to have a basic understanding of volume and intensity and a working knowledge of what your 1RM is...It might not be effective for calculating certain Olympic lifting set and reps progressions or be applicable to some individuals..But as a guideline for strength training, IME it's a reliable little piece of dogma and the stronger you get, the more accurate it seems to become.