I also have thin hair as does my wife and daughters! My son is the only one with thick hair, but he keeps it very short.

Never the less, for me the HHT is a marker of when my razor is shave ready. If I get a razor to pass the HHT effortlessly all along the length of the edge with one of my ladys' hairs, I know I will get a very comfortable shave from the razor. The quality of passing the HHT is important and I'm very happy to finally have a decent marker aside from shaving.