Nah, he was only pretending to be an artist sharing the hag's artistic sense. Obviously in reality they were lightyears apart. Brook is a rocking musician, the hag was... Dunno, a hypocritical expressionist or something. Fighting isn't the point for Brook, even if he can do it really well. Though he does even that rather artistically, if you think about it, and for example compare his sword fights with Zoro's.