If operation takes more than human's average reaction time, progress should be shown. Usually 250ms. Jef Raskin and others wrote a bookshelf about that a decade ago, but I still see strange solutions everywhere.

In this case it's showing a 24 progress bars each for an item that takes less than 1ms.

This is basically what happens in third-party tools. For example if you use 7-Zip on Windows to unzip multiple archives, there is only one progress window and progress bar, and it will display the names of each archive being extracted one after another.