Pillar dancing is not without risks, however. Faster monsters will simply catch up to you, rendering the process pointless. Due to speed randomisation, even enemies with equal speed will occasionally be able to act against you, possibly negating any health restored. Wandering monsters may stumble upon you as you're running, making the eventual fight that much harder. Even the cost of running can work against you; races with difficult dietary needs may not wish to spend turns needlessly.
That being said, it's still a situationally useful technique. It can minimize damage received while a caster recovers the point or two of MP needed for one last spell, and players with quickened HP regeneration can often outpace any damage taken. Fast characters will have an easier time of it, but are usually better off simply escaping the enemy and running upstairs to rest.
Prior to 0.6, monster speed was fixed, making pillar dancing much safer.