Tile maps are still experimental in 4.7 (primarily due to lack of proper collision generation) but they are much improved over previous versions.
However, system was not designed (and never will be) for a 10k x 10k map, that is an absurd size (400 M vertices for a fully populated map; I’m actually amazed it didn’t crash OOM). I’d expect for most games to use maps on order of 30x20 to 100x100 tiles, and use multiple maps where necessary to handle larger areas. culling system for UE4 works on a per-component basis, so you won’t be getting any culling for invisible tiles on a map that is much larger than could ever be seen at once.