I managed to get 100% at an area and I can tell you it brings some bonus (I have Qi gathered + 0,25% for example)
I'm trying to get a Qi Core, and the important thing is you have to have 10 in "balanced affinity, only the lowest affinity rate is indicated, so you have to level them up equally, I'm near 4% right nowbut it gets quicker as you level up the cultivation action rank