People should be judged on output not by the number of hours worked. What it takes one person an hour to complete could take someone else five hours. In his 1975 book, The Mythical Man Month , Fred Brooks studied the productivity of programmers within an organization. One of IT's biggest challenges is time management. The Internet has removed distance from the time, rate and distance equation.
Location is no longer relevant.
Machines get faster and faster affecting rate, but we haven't improved time. It is our most precious resource. A time tracking system is one way to find out how people are spending their time. You would like to ensure that people are only spending time on things that directly link to the creation of value or wealth. People need to know that they are contributing to value generation.