Welp, that gives a second (and much less cynical) reason for why you can't print in pure black n' white without colour being topped up.
Concern about counterfeiting just served as a usefully palatable justification for introducing the tracking technologies. After that, it's easy. All you have to do is let some small to medium counterfeiters continue to operate so the justification continues to look reasonable. Heck you can even do your more or less best to try to catch them all, since you can be confident you won't ever completely succeed
The worst damage crime does isn't direct. The real damage is the PR cover it provides for government repression
The white is, of course, the areas on the paper that you're not printing, assuming you're feeding in white paper.