That's because you're stupid.

[Lonely Paper Star]

You know, I will say, that FFX's battle system made sense in those regards. Like, only 3 people are fighting at a time, but the WHOLE PARTY is always at your disposal, cos they're all traveling together.

Well they are on a pilgrimage together, splitting up would be unnecessary. Also, if they all travelling together, why can't they just gang up on the bad guys? Is there some courtesy system in Spira where only three can fight at once?

I always thought it was weird that only three could fight at once... and if they die, it's game over. Wouldn't it make sense for the rest of the team to take over in case that happened?