I've stumbled across a bug, or maybe oversight, with which while all colonists are in the cave there seems to be an issue with the game generating quests and trade caravans. Not sure if that's some base game shenanigans or maybe intended behavior, but I'd say it's something to consider if you spend a lot of time in the caves. That said I do realize that the issue is quite niche and likely not many people would come across it but I figured I'd say something.
Also, it seems that raids also can't happen while all colonists are in the cave. I tried forcing all three interactions with dev mode, both with the camera focus in the cave and on the surface, and each time nothing happened. But when I sent one of my colonists out of the cave the dev commands did work.