So you are running an instance for upgrades for your character but are not interested in upgrades for your character. Funny isn't it? Artifact power is the same as loot dropping. You don't see a benefit right away and at higher amounts you won't see it for a while. But each little bit will upgrade your character sooner. A guaranteed goal that isn't RNG in the slightest. So you don't like guaranteed power upgrades. You don't like RNG power upgrades.
Sounds like WoW isn't the game for you in the slightest.