A lot of people had speculated it might be a skimmer underwater skill, which not exactly fit into the theme of the new map. But after I got the mastery unlocked for it, I realized what it was meant to help with. All those snipers just about everywhere trying to fill you with holes aplenty.
It started as 5s stealth on 40s cd
But now after the new build? It got buffed to 8s stealth on 30s cd, and adding 8s of regen.
That is really REALLY good to deal with ranged mobs trying to hit you. Primarilly using Skyscale myself, and using dash a lot, Ive not felt too bothered by the snipers. But its useful for when out of endurance.