In the GBA version of the game, I thought Edward was quite useful, particularly near the end of the game in the final dungeon. Certain enemies that would normally take a couple of hits from Cecil's Ragnarok, he could dispatch them in one stance without the enemy ever getting in a single turn using Apollo's Harp. Those who confronted Gold Dragon before will understand how annoying he can be with the Entangle technique, but they're like ants in the face of Edward. For whatever reason, creatures of this type are very weak against the "sun's power" that runs thru the harp, likewise for Holy-weak monsters.

That said, he's not the type you'd want in a boss fight a la Zeromus's magnitude. In this situation, his damage is pathetic and his HP was no help against the Big Bang attack.

If you can time Hide well enough, he can be useful. Which is what I did, along with Kain's Jump.

Ya, I did manage to utilise the 'hide then sneak attack' strategy quite successfully. Just that, the fight became a whole lot more protracted than need be compared to when I used other characters like Rydia, Yang and Edge etc. I'd pick them over Edward any day if it weren't for the perfectionist in me wanting to unlock his trial in Lunar Ruins.

If you take the time to get Edward leveled up; he is actually very useful with his varying status affecting harps. The charm harp is totally awesome. It charms your enemy and deals decent damage.