We learn mussar seforim as a way to improve our character.
Not necessarily – that is, simply learning from a sefer is generally not enough to
improve a person’s character (although learning b’hispa’alus might be?).
We might learn them to learn practical methods of improving ourselves,
to lift our attention from worldly thoughts to the subjects of mussar, etc.
(The bochur who asked a gadol, “How many times a zman should a
bochur finish Mesilas Yeshorim?” was laboring under an illusion.)