My opponent cast Outrageous Robbery on me where X = 3. I won the game next turn, but the three face-down exiled cards that I own (under opponent's control) were not turned up after the end of the game. In a paper game, I would recover all of the cards I own before going to the next game. The reason I think this matters is that it could have been useful information in a best-of-three scenario, where I would want to know which of my cards my opponent chose not to play. That information would give me a strategic advantage, and influence my sideboarding decisions.

Arena fails to reproduce the information that a player obtains from their own physical cards when transitioning between games of a match.