Their Final Fantasy knowledge can help them build their first deck during a pre-release event, something that wouldn't have worked had Wizards of the Coast not made the effort to really solidify the set's flavor
In a counters-focused combat deck, Miles snowballs into massive, unstoppable swings
These colors all help the strategy quite a bit and have plenty of support cards released for them over the years
Outside of Standard, though, perhaps the competitive format most impacted by Final Fantasy is Duel Commander
Frodo, Adventurous Hobbit + Sam, Loyal Attendant Another pair of partner commanders, Frodo, Adventurous Hobbit and Sam, Loyal Attendant work even better together than Merry and Pippin as perhaps the best Food commanders in Magic
I love the power of this thing loads, but like the Carpet showed, there are a lot of flyers running around that will slip over the Castle's Moat