To use bound weapon effectively, you need to put perks into weapon skills.
There is an alternative to this approach. Iron daggers and Long bows with no perks in one-handed or archery. If you get elemental perks in enchanting and destruction, you can get enchanting damage quite high. You can get 20 fire damage in early game, 40 fire damage in mid game and when you get your enchanting to 100 and get double enchanting perk, the damage can go up to around 160 with 0 skill and 0 perk in archery. If you have elemental damage perks in all 3 schools you can carry around 3 long bows that does 160 damage or more depending on the opponent immunity or weakness. Fire Atronachs are immune to fire attack but very weak to frost, so it would be ideal to use frost + shock. Mammoths have resistance to frost, so it would be best to use fire + shock. If they are not immune to either, ice + fire. Ice + fire bow for the storm atronach.
Spoiler
Bound Bow is really fun to play with. If your Conjuration skill is above 50, you can buy it from Phinis Gestor at College of Winterhold.
One popular place to get Bound Bow spell early is at Fort Amol. It's inside a bucket so it's easy to miss unless you know it's there.