I did, but maybe I need to explain exactly how bonkers it is!
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Ok, so you have 36 charges and you can choose your level of protection. "Keeps out non-living matter" protects you from most weapons you'll be attacked with, and "Keeps out living matter" will protect you from most creatures. Sure, some attacks are going to cost extra (I'd be annoyed spending 4 charges to ward myself from magic only to have to spend another 4 to stop a lousy
lightning bolt), but there's still a lot of uses for this item! Not to mention that while the listed spells cannot be cast into or out of the cube, other spells can be, and this is the only time the Cube mentions that the barrier works both ways- though I'm sure most DM's will insist on that point the first time your party Wizard makes themselves unassailable and starts going nuts with
cone of cold!