It multisamples reflective surfaces and shadows. If it didn't there'd be no difference between 2 reflection samples and 20. The only thing it doesn't do is multisampling on triangle edges.
Even if it's the 'highly irrelevant to practical physics or understanding of the universe boson', it's still a big deal -- we haven't discovered a new particle in almost 20 years.
Hey this might help. Its still confusing if you ask me. http://udn.epicgames.com/Three/SettingUpVehicles.html#Modeling%20Vehicles%20-%20Setup%20and%20Rigging