There are a myriad of both automatic and manual time tracking products for the Mac. The reason for each category to exist is because some users prefer an automated workflow (even if it's not optimal), while others like a more controlled way to tell the software how and when to log hours.

FreelanceStation is in the latter category. Being a manual time tracking application, you control when and how much time you log. There is no need to setup rules, review logged time to see what's billed and what's time unrelated to your project, or fight against a rule engine that's too smart but not always enough to understand how you work. The simplest workflow is to just click on the timer button to start it, and then click it again to stop it after you have finished working. That's it! No dragging and dropping time slots or assigning categories of work.

Why Automated Time Tracking?

People come in different shapes and colors. Diversity is good. We also tend to like different things and have varying workflows.
Some people like to micromanage every single second and activity of their days, see how much time they used while browsing cat pictures or chatting with friends. FreelanceStation was not built with that purpose and that's why it will only ever support manual time tracking.