I find a halberd helps on the tricky climbing areas and on overly crowded trails where people refuse to hike single file.
More seriously, I've never felt both poles help me much, but one pole helps on long or steep climbs. Since most of the best trails around here are in flooding zones around rivers and the trails seem to cut to maximize distances there are lot of up and down sections.
I have been using a staff for decades for backpacking it has save me from falling many times.