I used Enemy Skill all the time. It provided the ability to target all opponents with many of the spells. Aqualung, being one of the few water spells, and Pandora's Box are great for dealing massive damage to wipe out some tougher random battles. White Wind can be great for boss battles over Cure3-All. Matra Magic is also great for early battles as it costs only 8MP and deals non-elemental damage.