Dual Wield vs. 2 Handers for Monks

[Yaolin]

Everything I've ever read points to the fact that monks should use Peacebringer, IFS, and T-Staff over every other 1 Hander combination other than EPIC fist and SoS. My question is, if you could afford to buy a T-Staff, Peacebringer, or IFS why do you still choose to use 1 Hand combos? This question only applies to monks above lvl 30 after the damage caps have been removed.