I just finished lb 1, is mashs new skillsset supposed to be worse than her original skillset or am I using it wrong ?

So like what's the point of going from an actual tank who guards her allies to... Buster crit build who still has shit damage and still isn't effective against anything? Is there anything I am missing here because what reason is there to use this build over the original skillset when she isn't story locked to her new skillset for whatever reason ?

So like what's the point of going from an actual tank who guards her allies to... Buster crit build who still has shit damage and still isn't effective against anything? Is there anything I am missing here because what reason is there to use this build over the original skillset when she isn't story locked to her new skillset for whatever reason ?