Yes and no. Players have reported that they can gather large quantities of crystal from running vaults, however, I didn't see those results myself. I did a couple of vault runs, killing every enemy in the dungeon and looting the end chests, and I didn't find even one pitiful handful of crystals. The loot pool appears quite varied so I may have just got unlucky, but if I wanted to gather crystal, I'd stick to the traditional methods. It may be a little slower, but at least it's undeniably consistent.   Once you've acquired enough crystals, you can finally have the ever-useful Map Room!