That's an inconsistency of rules, inconsistency is bad design.
IIRC you lose memory from the Ring of Braccus Rex(-1), and there are hopefully going to be other items with similar trade-offs.
Not necessarily. The ONLY times it comes up is a single item.
It completely and utterly doesn't matter... AND isn't the only game to do this.
Better yet the ring retains the rules either way. -1 to memory at 10... = 1 less memory stat.