When you sit in the exit row on a plane you are required to give a verbal commitment.
You commit, by agreeing out loud, to do all you can to help the entire set of passengers get out in case of an emergency.
When you say “yes”, you’re saying, “I’m prepared to be a leader,” and to do what the 143 or 175 or 300 others need you to do, according to the specific instructions.
The others are on your team. You’re sharing an experience and have the same set of guidelines. For the duration of the flight you are a team.
As a leader your get some more leg room. That’s it. It may or may not be worth it. And even if you’re in the middle in the last row, the flight will be better if you are on board with the rules of being on board.