I did not see that discussion, but the implication given in the demo's and interviews went further than just battle.
A made up example : You could in principle send a scout to the mountain pass (and discover it was guarded by Githyanki) while at the same time another scouting party went down the ladder to the underdark to see if that path was protected.
Yeah, But I'm SPECIFICALLY talking of how this feature (splitting the party and doing different things at the same time) could cohexist with a day/night cycle.
NOT of what you could do when splitting.
To be clear, personally I don't even value co-op and being able to splitting the party that much - and I would gladly trade the feature with a day/night cycle given the choice- but it's pretty clear that Larian considers it a cornerstone of their design and an a valuable feature to offer players, which is why I make an attempt to find a compromise.
