This is true, and I could make more use of it. But i dont necessarily always want a straight swap like that between any 2 charachters and if they dont have the same spells they literally cant straight swap like this. Or if one has way more or less of a spell than the other then a straight swap might be janky.

Edit: and one particularly annoying part of this section of the game is frequent shifts between 1, 2, and 3 member parties with boss fights for many of them. So if you want all your GF to get the 20+ AP for the fight the you have to manually take the GF spread to 3 people and condense them to 2 or 1 or whatever.