It tests the bearing resistance, that's all, and the grease and packing and adjustment with older components.
It is fun to show people, though.

More fun with older Campy than others. Not so fun with modern stuff with sealed bearings on bb's and hubs.
However, if the new stuff was more "resistant," you'd not see it on pro-level competition where money depends on winning.

At least that's what I tell myself. I still prefer a Campy ball bearing bottom bracket to all others, and Dura Ace ball bearing hubs.