Never depend on crits for healing, but when you do get a crit you get extra healing for zero extra sp cost. It's basically free healing, why not maximize your chances for a crit? Especially whenever you are spamming mass cures one after another. Of course the VoD gloves are better, especially if you are specced for damage, but you'll be competing with every other arcane caster to get them. People practically throw away the gauntlets from the reaver.