That's a good question. I suppose it's trying to emulate the combat feel of perhaps a shooter, because one of the spell schools is basically a long range weapon so the triggers makes it feel like a shooter in a way. But that breaks down when you swap to the melee spell school and you wonder why you could just have both schools active and put the melee spells on square and triangle and leave the ranged shit to the triggers. That would make sense.
I think there also is a problem where the japanese don't seem to understand open world game design in general. They think size is what makes an open-world great (Elden Ring, Breath of the Wild, XenoBlade, etc) Too often the maps are just empty with vast distances between things that are interesting and what's actually interesting is often repetitive.
I think the only Japanese games that do open world well are the Yakuza games.