I don't really care for the barbarian arc . And it's pretty stupid he didn't keep a skill like super regeneration...
Agree to disagree, not only it showcases a different side to the world, Bichir come to learn archery and other stuff outside of Baskerville teachings, which is a hidden blade in his repertoire that might help surprise Hugo when it's time to kill him.
Also good to humble Bichir, that he's not so OP that he can escape consequences, but not too wimpy that he can't pave a way despite all that.