Feedback: UI - I don't understand this quest reward and there is no explanation

I am looking at the "Den of Snakes Reward" from Servi in act 3.
She offers 3 vails, one of which is "Grants 30% increased Elemental Ailment Threshold". When I hold Alt key the only phrase with help text is "Quest item":)

So GGG, what's Elemental Ailment Threshold? Please add an explanation.

I believe it's the amount of elemental damage you can take before an elemental debuff will get applied to you. The warrior has "stun threshold" passive buffs, so I'm assuming it's the same for elements.

Do we know how significant the 30% element threshold is?

Assuming as it's permanent, it's considered so insignificant that the choice does not matter (or at least that's my hope!) but in which case - why give us the choice in the first place without being able to change it like the Act 2 reward?

we need a way to change the reward buff for builds. Please make it a changeable node or able to switch for gold