When developers give their character’s personality, it’s one consistent with what they do in the game. Namely, the writers give them a personality that makes the characters receptive towards completing side quests and mini-games.
Final Fantasy I, II, and III really don’t have mini-games or side quest in their original games. But in the remakes, it makes sense for the main characters in I and III to participate in them. They’re essentially adventurers. In Final Fantasy II, the main characters are more concerned with whatever can help them defeat the Emperor.
Cecil engages in one long side quest to help Rydia and Yang. He does so in accordance with seeking redemption.
Bartz is an adventure, in the vein of Final Fantasy I and III. Of course, he just seems like a pretty easy going guy in general. His personality is that of a drifter, so you’ll find yourself wasting time with his harem.
Final Fantasy VI has no set character that must be in the party at all time. But each character rebuilds themselves and their team. Your characters engage in one long side quest to find your team.
Zidane’s motto is “You don’t need a reason to help people”. Likewise, you don’t need a reason to jump rope, play cards or find Chocographs in Final Fantasy IX. If you feel like it, do it. If it helps people feel good, it was right.
Tidus can’t help but help people out and Yuna can’t say no. Together they’re the reason you’d take on a lot of side-quests and mini-games in Final Fantasy X and X-2. Not to mention that Tidus is an expert in Blitzball, and Yuna takes after him!
In Final Fantasy XI and XIV, you’re an adventurer. Like in Final Fantasy I and III, you roam the world looking for people to help, and places to explore.
Vaan, Penelo and everyone else is basically outlaws. Ashe desires more power, and probably take on hunts just to make ends meet. And get enough license to wear that one piece of armor…
Final Fantasy XIII doesn’t have any mini-games. No surprise there: Lightning is on the run and extremely no-nonsense. She wouldn’t have time for this. Serah does some mini-games in the sequel, but only in the service of resolving time paradoxes. And in Lightning Returns, Lightning only helps others if she believes it’ll extend time.
Noctis was a “man of the people”, but he just comes off like a pushover. Does he have to take so many side quests? He has a heart, so he’ll help others when he can in Final Fantasy XV. Plus, he and his bros are essentially like adventurers, in that they’re on a road trip.
The only two people, and team for this matter, that this doesn’t truly make sense for is Cloud and Squall. Why would an ex-SOLDIER participate in so many mini-games? Maybe because this is something Zack would do, but why would everyone else just let him? What about Squall? Even though he’s a teenager, he seems pretty no-nonsense himself. Would he have time for card games? Maybe if they were in the service of getting better magic. Perhaps Balamb garden indoctrinates their students with the “correct way” to spend their free time?