I used earth and moon/ysgith runes for my steel and silver swords respectively. Was about to reply, then decided to check the rune stats on the wiki first, now I realize why people go on about fire and ysgith runes. The equipment overhaul mod I use changed the effects of the runes. lol
Only if you consider crit to be extra damage. DoT effects may not be high, but i think all the crit effects are useful otherwise. Slowed enemies are easier to attack because they don't block well. On fire enemies don't attack back, etc.
I loved stun + one hit. Made my hard build mostly around arden + crit then one shot. Unfortunately the stupid cut scenes got me killed more than a few times. >.