In the 3D program Maya, why is the uValue 0 to 1 when attaching an object to a path in cm and .000 to .001 in meters?

Answer 1

Values are often measured as "floating" values, meaning there is a practically infinite number of decimal places adjusting values between "0" or "off" and "1" or "on".

The uValue is a relative metric (relative to the path you're referring to) as opposed to a fixed space metric, like meter or cm.