World Smallest Brush, what the scientists created

I just don't understand. Will smallest stuff means better? Then how bout those peoples with big hand?

Mehrdad Ghasemi-Nejhad, a professor of mechanical engineering at the university, said the brush may be used to sweep nano dust, paint small micro-tubes and clean pollutants in water.

Nanotechnology involves the manufacture and manipulation of materials at the molecular or atomic level. At that scale, materials are measured in nanometers or billionths of a meter.

This is just weird.