I need clarification regarding adding Large DataPage to whitelist

As per Pega Documentation

After you create the data page, declare it as a large data page.

To do this, edit the whitelist for the List of data pages that are available offline but are not referenced directly in the UI.

Add the name of the data page followed by ;large. For example, to declare the data page D_FieldMappings as large, enter D_FieldMappings;large in the HTML source. Add additional large data pages on separate lines.

So my question is adding large DataPages but referenced in UI in white list won't help to improve Performance? even though is datapage referenced in UI also added in to whitelist- still synchronization required- synchronization takes place?[since added to whitelist]

But adding datapage [ whether the datapage is copying data or referencing and loading not mentioned] only said is used in UI is added to whitelist would improve performance or not

My question is Performance would improve or not.

***Edited by Moderator Marissa to update SR Details***