Purpose of overriding deleteRecords method in detail's modal lookup window example

Does anyone know the purpose of the overriding of the deleteRecords method in Step 3 of the following Academy article on using a modal lookup window to populate a detail? https://academy.creatio.com/documents/technic-sdk/7-15/creating-detail-selection-lookup

When I remove this, it doesn't seem to have any impact on deleting records from the detail, and I can't tell what it's trying to achieve by lookup at the code and the vanilla deleteRecords method.