My understanding is that “REPEATER” functionality will go away in the near future - please vote for this and help keep this great tool in service!
In short, REPEATER allows advanced CL admins to create automated testing where you can refer to an excel spreadsheet to get values. This is more useful than CASES because you have the ability to randomly get variables in Excel (with formulas) which makes testing much more useful. Often times yu will get a list of items from Operations in an excel sheet and it is very easier to transform those values into a REPEATER template.
With REPEATER, I can easily create 100 random requests/tasks based on formulas I write in excel. While CASES are very beneficial and they have unique features with the xml file, it doesn’t replace REPEATER. PLEASE VOTE to keep this.