parRepeater Allows the user to store parameter CSVs like 1.csv, 2.csv……up to [parRepeater].csv, then in the flow individual parameters can be read using parCurrentRepeater & ".csv" which will change the underlying parameters. So it offers flexibility to control quite a few things – not only parameters. This is one example but it's up to user how they would like to use it. DataType is Boolean.
parParametersFile is the parameter which will be modified in EventHook Assign by overriding it's value to be evaluated based on parCurrentRepeater.
Bulk copy for SQL SERVER
Bulk copy is fast load of synthetically generated data. So when you want to load large volume of synthetic data it's good however it's only available for SQL Server. Also user loses the ability to perform action on individual row that is being generated so BCP has it's own limitation. DataType is Integer.