Originally Posted by Kevin Ray

This is because most people who say this are merely miss-speaking. What they are actually referring to is the ability of non-powered wheels to roll. For example if an macanum drive bot were to be pushed from the side (straffing) it would "roll" as though it had no traction.

Originally Posted by IndySam

They're not by people who understand them.

In a pure pushing match they perform well. They can suffer from gearing problems because they generally have to be geared high for good speed and are rarely used with shifting gearboxes so they can suffer when it comes to power.