This allows you to detect changes in a lightweight manner via the Transaction Log in SQL Server in combination with T-SQL. Change Data Capture is more about auditing or creating a historical view and Temporal Tables are the next step up from there which became available in 2016 versions of SQL Server. Change Tracking is primarily used for finding only things that have changed. Not necessarily why, how, or who changed it, but what has changed and what it is now.
So why would you want this technology implemented? I find this technology is best suited for tasks where I want as light of a footprint as possible and I want to bring over incremental changes.
Click through for a long and complete walkthrough. If you’re thinking to implement change tracking, this is a good link to check out.