In WT4 your main task is to get full Ancestral gear with the right stats.
But it seems that “Purveyors of Curiosities” only roll normal & sacred item but no Ancestrals (spent about 15k Obolos in WT4, not 1 Ancestral).
This means that world events and Obolos are prety much worthles in endgame if you want to min/max your charactrer.
It’s sad because I like the world events and “Kadala” gamble with the currency you get there.
Yes you can buy whispering key but you don’t need them that often because the silent chests are prety rare.
I hope that this will be adjusted in future, so Fideg & Co can also drop Ancestrals and being relevant even in endgame (like Gheed & Kadala in D2 & 3).
You can absolutely get ancestrals from the gambling npcs. Before gambling, ensure the piece you want has the ancestral border and says ancestral on the image. Sometimes a vendor will have 1-3 pieces while the rest are sacred, sometimes they will have none. Each gambling npc has a different inventory of what they’re gambling as ancestral rank. Now this doesn’t mean every gamble will be ancestral, just they’re more likely to drop as ancestral. If it doesn’t say it at all, don’t bother spending obols on it. If you’re getting close to cap/are capped on obols and none of the npcs have ancestral gambling (highly unlikely), just buy a few keys.
Ancestrals from trading become common at higher level, which makes perfect sense as obols are not Tier locked (you can use obols from any tier in any tier, hence WT4 by itself doesn’t provide better reward and it’s instead tied to your level).