[sciurius]

The differences between set lists and collections is subtle and both can be used for very similar things.

Let's not forget that MSPro is a tool for musicians to view sheet music while performing.
A collection is a sorted list of songs, no duplicates.
A set list is a user ordered list of songs, possibly with duplicates. And set lists have additional features that come in handy when performing. E.g. set list notes and the ability to view all songs one after another.

There are collections and lists for a reason.

I don't have the Collection tab displayed as I didn't / don't have any use for it.

Apparently, you do have a use for it.