The advantage of that action is that you don't have to first select all items in Arrange.
But, If OP just wants to delete the area falling into Time Selection
without moving later items, there even seems to be no native way to do that in Reaper.
Ideally there should be be an Action for that case : "Time selection: Remove contents of time selection"
But that doesn't exist.
Therefore, i made a custom action:
https://i.imgur.com/oQf97wl.png
So this Action will delete the area falling into Time Selection, without moving later items and without the need to first having to select all items in Arrange.
Maybe there are easier ways to accomplish this, dunno ATM.