I think the inference is that people can tell a difference, but cant reliably state the joint type just by the hit.
Makes sense, but if you can tell a difference, then you might have a preference.
Could be useful within a single manufacturers product line where everything except the joint is the same. For example, the pictures I posted are Mezz joints. The Mezz Wavy Joint has a softer hit/feel than the Mezz United Joint.