Board Thread:Questions and Answers/@comment-24.12.208.46-20180824172124/@comment-36170150-20180824174742

Only the people that participated get the EXP for that fight (because everyone else gets temporarly removed from the party, you can notice it in the formation screen before the battle) so Simon will have slightly less EXP, but it shouldn't matter if you have been thorough with hunting down enemies (at least for the LVL checks currently in the game).

You are right that the -10 Dari RP are irrelevant if you're thorough with her RP gains.

All the other tradeoffs will be related to the BoY itself, if you don't need the "Assault mage tower" option in your run then you don't miss anything else.