Originally Posted by jpc
Speaking generally, the higher the wear rating, the harder the tire (with all else being equal, which it pretty much never is). That translates directly into less grip, which means less safety (under braking, when turning, etc.).
That sounds good in theory, but not sure how it holds out in practice across the board. In addition to the treadwear number is the traction letter indicator in the UTQG, AA, A, B, and C. These describe the straight wet line coefficient of traction, more or less straight line wet braking performance.
Point being, sorta what you already covered, is that usually all things are not equal so going just by one metric seldom gives the complete picture.