When doing ETL projects, often many Package development is based on the same model and process. For example, you need to insert records into the Process log table when the Package starts running, and update the running state at the end of the Package run.
All Package in the same project in the error-handling phase are also handled the same way, in addition to the configuration of the design to the Package, as well as some parameters and validation processes, and so on are basically consistent.
If you need to drag these controls and configure the Connection Manager each time you develop a Package, configure the SQL statements and parameters, and make sure that everything is configured correctly, it will take a lot of unnecessary effort and time, especially when different developers may be naming and configuration and specification if inconsistent in the post maintenance phase is a very troublesome thing.