I vaguely remember using these as a younger network engineer and possibly not understanding them well. It was just our SOP (Standard Operating Procedure) to apply the macro to the interface as the switch was set up or modified.
These are pretty simple to understand and save heaps of time. :)
The old way is below. Here you define the macro first and apply them to the ports that require it.
The new way (which I think seems a lot less intuitive), firstly you define the ports you want and then apply to macro to them.