What difficulty are you on? On master/legendary they stop being as effective once you get past level 20. The enemies seem to get a big HP boost around then
If you enchant for one handed damage, the swords should be viable dual wielded at any level on adept I would think.
Dual wielding bound swords is pretty good actually. You attack super fast
i use bound swords against weaker nasties. bound swords can capture souls for the black star. i use an enchanted dragon sword with absorb health for tougher nasties. this way the enchanted sword doesn't need to be recharged as often.
the thing is to experiment and see what works and what doesn't.
I use a bound bow on my witch hunter character, never had any issues with it, it seems like a strong reliable bow. I play on adept too.
I had a spell sword that used bound sword in one hand and a distruction spell in the other. Now he did wear light armor and I perked up 1h along with conjuration. I didn't use smithing as his craft, that was enchanting, though he did smith his and his followers armor and weapons ( for followers). using enchanted gear and smithing potions. So not uber smithed. He was actually slightly OP at lvl 47 when I retired him. ( his RP was done) His only back up sword was Dawnbreaker, which mainly he used on the undead....cause it's cool.
My sorceress is pressently level 71 and still uses the bound weapons with no problem. She can still 1-shot an enemy with bound bow, and do really good damage with both bound sword and bound dagger. There is a perk I take under conjuration that gives 50% more damage for bound weapopns. Also, my gals love to sneak, and under the sneak tree, there is deadly aim which gives 3x more damage when using a bow in sneak, which also covers the bound bow. One can also use poisons on bound weapons. I play on adept