The HHT is useful when you know what you're dealing with. I can't help but feel it's of less use to the inexperienced.
The Wiki article is a good guide on gaining an understanding of how to use it to assess the edge, but for many of those new to the game, it can either pass the HHT, or it's not honed right, & that's the problem.
Personally, I must admit I do incorporate it, but I don't consider a pass to be the benchmark of a finished blade.