Even with a longbow you'll get more energy back with a zealous mod than you would from the extra pip of regen, provided you're attacking and hitting things. And if you use a short bow the energy gain will be very noticeable. You just have to remember to swap out to something else while you're not attacking.
With a short bow, and any kind of attack speed boost at all, or with multiple shot skills like barrage, the energy gain essentially means you are never short on energy. The only time it is worthless is if you are not hitting anyway, in which case you have other problems...
With barrage it is very popular. You gain 5 energy each shot provided each arrow hits a monster It owns in toms, it enables u to constantly spam barrage, aswell as any healing needed