Guild Wars 2

I see it in all the meta builds but isn’t it only up like 2/3rds the time? Whereas you could take vital striking, or stone splinters for more damage and have it up all the time? This is primarily in regards to dungeons.

You need the points in air for more precision. That said often times it’s the only relevant trait to take.

Well Air doesn’t offer better options if you’re going for the grandmaster and air gives additional precision.
You can almost keep it up 100% of the time.

I would still say, that it depends on your weapon set and your rotation.

Arcane Lighting can be maintain 100% of the time. And anyway most ppl want to get the vulnerability on crit, the added precision and ferocity and Tempest Defense. So Arcane Lighting is the best option. You can replace it by Air Training for a better Icebow/Glyph of Storm burst, but that’s all.