Originally Posted by
Iscah
Obviously it's not "mandatory" in terms of being able to make progress in other parts on the game, but it's not self-contained and fully optional either.
A lot of people are after the "relic weapons" that require Eureka completion and a lot of grinding in there.
I'm more interested in the game's story and lore, and Eureka isn't self-contained but answers a hanging question from the MSQ - the fate of the Isle of Val, first talked about back in 2.X. If I want a full understanding of what happened, Eureka doesn't feel optional any more.