Originally Posted by
BillyKaplan
but that's... all you do in Eureka? You grind light, exp, and crystals. Everything in there is geared towards your progression. Lockboxes are not only gated behind a tons of RNG, but you're also incorrect about getting 'only progress' from running other forms of content. You could farm glamour while you were at it, or minions. Basically the same thing you do in Eureka, only there if you ran it solo you didn't have to fight the entire instance for a bunny, whose chest would most likely give you materia you don't need.