it lets you place maps inside other maps via an entity.
That’s right, have an arch appear a million times on a building and aren’t sure how the final texture and structure will be? Make an instance and then adjust one single arches texturing and structure and have it appear across the whole building!
Have a few buildings that are at funny angles, dont want to have to make it to perfection, then rotate it for fear of screwing something up? make an instance and then build the building ON THE GRID and import it into your main map! Rotate to hearts content with zero problems!
Have a loading zone? want to make sure it’s exactly the same? make the loading zone an instance and have that in each map, guarantee your changes will appear on both maps with no effort gained!
Have multiple maps and want to see how they are all connecting and that they never overlap? why not import them both into a new map and see how they fit together!
oh god, so good
-edit- My favourite is the rotating of objects, circular building are finally easier and off the grid mapping is also now actually plausible. The HUGE difference that not having everything at 90 degrees makes to a map is amazing, so much more natural.