Vaal skills can't be used on boss fights? Why?

So what is the point of vaal skills if i can't use them when they are most needed?

I'm talking about Vaal Grace and Vaal haste. I can't use any of them during the hardest boss fights, like Izaro and Elder generals. Whenever i go into their arena both vaal skills are disabled, saying they don't have enough souls.

You can't use it on Izaro because of how the lab works, there is a town area(with stash) right before the fight and the boss room is classed as a new instance, as are the elder guardians boss fights (new area, none of the map mods etc)

The real question is why you don't get vaal souls from mobs in uber elder fight. But yeah overall vaal skills are absolute trash except for mapping. Only useful ones are the auras.

At some level, some vaal skills are seen as being an "I win" button. They don't want you to have access to that during some stages of the game. Pretty obvious in some cases.

They need to make it so that hitting certain unique bosses generates vaal souls. That way you have to do a portion of the fight without them but then you do have them for a potenially clutch moment later in the fight.

GGG basically gave up on the idea of vaal skills long ago. When was the last time vaal skills were even mentioned either in patch notes or new unique item mods, apart from explaining the new soul cost progression in 3.0?

i've always thought vaal skills should gain souls over time, i don't know what they have against this they really aren't that broken since they gutted lightning trap. Plus anything that buffs the slower speed builds is a good thing in my book.

Might work as a modification to Vaal Pact... 1 soul per 1000 life leached or something.

I barely ever as in so seldom as to 'not at all' use Vaal skills because of the 'soul' cost. They're almost unnecessary while mapping, and not usable in most boss fights (even fights with plenty of adds that replenish potions).

They need a full re-work along with other skills in 3.3 - They should either have timers, or work 'on hit' rather than souls.

If you realllllllly want vaal skills during these fight, you can get them with Pathfinder (or scion pathfinder) + flesh and spirit + worm jar :D