>>719025261
It's really expensive early and requires a very particular quartz setup. Later on (really, moreso in the sequel) bosses can one- or two-hit kill you, so it becomes more necessary to survive.
Combat in these games is mostly about maximizing turn efficiency. Taking one turn on your character to cancel out several attacks from the opponents is therefore an inherently strong move. The clock up/down arts and action quartz are also important for similar reasons.
