Aye, it gets really good in Null Grids since you gain a massive amount of extra stats from it and starts to really show the difference. Obviously it is not always super practical to focus completly on it, but if the Hime is luckily one you wanna use anyways, she is gonna be a happy girl

Also note, this also counts for Souls. There is only one exception: D'Art doesnt get double the bonus having 2 times Guns noted. Every other Soul though gets bonus from both weapon types they favor.