You can visit anywhere in the world without the updates. They do contain fixes and additions to airports, photogrammetry, etc, though. So the general consensus is that you would probably want to install world updates for the areas where you’ll be flying most.
If you’re not sure where you want to fly or you want to fly everywhere, maybe just start with one WU area fly around all the places you want to over a few days. Then uninstall it and move on to the next.
You can also uninstall some aircraft and skins, etc in the content manager to help reclaim some space if you won’t fly them all.