Well, attack buffs are pretty lousy because they're usually adding to assault and thus their relative impact shrinks the more developed you are.
Defense related buffs (be it defense buffs, damage cuts, reflects, or element tolerance buffs) tend to maintain their relative impact. They're held back by their uptime being defined in turns. But they do come in handy for mitigating giant spikes in damage.
It's just that it's easy to dismiss them and be fine with just atk down + element advantage because it's not too often that we actually see GIGANTIC instances of damage in the current state of the game.