Why We Do This
The reason we assess effect is to set expectations and make the fictional situation more clear, so everyone is on the same page.
You tangle with Francesc’s enforcer, blade to blade. Do you inflict a grievous mortal wound? Do you only give them a shallow cut? Why are you having the effect that you have? How could it be worse? How could it be better?
By assessing effect and describing it in the fiction, the players understand how much progress they’re making and how much they’re risking. By understanding effect, the group understands how many actions (and risk of consequences) will be needed to achieve their goals. Maybe a shallow cut is all you need to prove your point. Maybe nothing short of death will suffice. After each instance of action, effect, and consequences, the players know where they stand, and can make informed decisions about what to do next.
If you’ve played other roleplaying games or video games, you’re probably familiar with the concept of “hit points” for a character or a progress bar during a boss fight. The effect system in Heroes in the Storm is this type of pacing mechanic, abstracted so it can apply to any type of situation, from fighting, to social manipulation, investigations, arcane powers, infiltration, whatever! Every action has an explicit effect that everyone playing the game can understand, either resolving the current situation so we can move on to the next one, or incrementing progress toward the current goal.