Wow, read what I said. Compare two spells that have the same damage type, same valid targets. The only difference is whether they are Direct or Indirect. Physical Damage, Physical Spell. Basically create an Indirect version of PowerBolt, call it Bullet.
Why would one use this Indirect spell? Against certain targets it might have a slightly higher chance of going through, but it is guaranteed to do less damage on average.
Direct vs. Indirect Resistance
Body (+Counterspelling) vs. Reaction (+Counterspelling) + Body + half Impact
"Average Mage" -> Call it Spellcasting Pool of 12, average hits of 4
"Average Troll" -> Body 7, Reaction 3, (no Counterspelling), Impact Armor 11
Powerbolt F5 = 2 avg. hits to resist -> 7 damage
Bullet F5 = 1 avg. hit to avoid -> 3 net hits, base damage 8 -> 4 avg. hits to reduce damage -> 4 damage
And that's against an enemy that has the highest chance to out-right resist the Powerbolt...
My argument isn't against the idea that different spells are used for different purposes, only the argument that Indirect Spells are inherently weaker, but still cost the same amount of drain (for otherwise identical spells).