Ghost no longer bound by walls in caves and clip through everything.
Not sure if it is intended or not but this allows you to skip content with the proper setup.
If you have lazy deserters setup. You could essentially die, float across void to fuelweaver, use an amulet you left there and teleport everyone to you. Bypassing the whole atrium content.
Same with in the overworld. You can float as a ghost to new lunar island bypassing ever needing to sail again except for the first time to setup.
Like I said not sure if intended or not since it allows you to skip some major content