That's only for the blaster-caster subclasses though. The subclasses that are more likely going to go into melee (mostly the ones who get heavy armor proficiency: Forge, Life, Tempest, Twilight, War, and many other subclasses) get Divine Strike instead. So a cleric build that takes 8 levels of the subclasses that get Potent Spellcasting would be unlikely to use True Strike by then, they'd likely hang back and spam Toll the Dead or Sacred Flame (or a ranged spell).

(Even with a heavy crossbow (that most blaster clerics aren't proficient with, but they can gain proficiency from racial features or multiclassing), at level 8: True Strike + 20 WIS + Potent Spellcasting = 1d10 + 1d6 + 5 + 5 = 19 average damage with +8 to hit; Toll the Dead + 20 WIS + Potent Spellcasting = 2d8/2d12 + 5 = 14/18 average damage with a save DC of 16. Not very much more powerful. And then you get to level 11 where TTD with Potent Spellcasting jumps to 3d8/3d12 + 5 = 18.5 / 24.5 average while True Strike with the heavy crossbow is 1d10 + 2d6 + 10 = 22.5. The cleric will more than likely spend the first turn setting up a buff/debuff/control spell, so the d12 damage dice will apply most of the time.)