There are many reasons that Time Tracker for Salesforce is different from other applications.

Tracks real-time: Time Tracker syncs data immediately, you see total time worked on any Project immediately once you have Checked-Out of the Project.

Check-In from Salesforce: If you are a Time Tracker User and also a Salesforce User, then you can track time in Salesforce for the Job you work on.

The users that do not have a Salesforce ID, can track time using the Time Tracker for Salesforce Web app.