Just because the game runs on UE4 doesnt mean it's guaranteed to work on the Switch. The dev's expertise, how demanding the game is, and many more factors are in play here.
For example, Ace Combat 7 runs at 720p at a very unstable 40-45 fps on the base xbox there's no way that runs on Switch. Because of the terrible optimization by the developer.
Bet with Intrinsic:
The Switch will outsell 3DS (based on VGchartz numbers), according to me, while Intrinsic thinks the opposite will hold true. One month avatar control for the loser's avatar.