Default cooldown of enchantment is four seconds. This trait shortens it so that it fires more often. There are gear sets which also affect it and they stack. A Torug's Pact powered weapon at legendary level triggers the enchantment nearly every hit. You need to recharge such weapons often.

This maybe useful for e.g. fire enchantment, especially if it synergizes with some other class or gear effects. If the enchantment is e.g. weapon power for five seconds, it's useless.

yeah.