There's no point, other than role-playing.
And TES is role-playing, right?
True, very true. But as any RPG, its a Game, that you also Role Play in. Otherwise it would just be an RP, yes?
That being said, theres always the people who will focus more on the RP side of things, and others (like myself) who focus on the G side of things. I personally will go out of my way to play with the numbers. I, personally, dont horde over them, cool factor plays in alot for me. But sometimes its just more cool to whip some ass, then to look cool while flailing around futilely. Othertimes, even if its not as effective, it's effective enough where it doesnt matter.
That, was more the point of this discussion.
Also, unless some one can source where its been said that you can do a dual weapon sneak attack, i'm not gana bank on that. Its an incredible amount of damage. Also, wouldnt you be able to do the same with swords, but still not get screwed in open combat?
Also, one must consider that all of the enchantments and poisons are exactly the same. The weapons would have to be a fair deal faster for the surplus DPS to stack up.
Also, consider your longetivity in combat. How long do you think those weapons will hold their enchantments before needing a refill? I remember in oblivion, if you didnt have a HORDE of soul stones, and some way to refill your enchants, you'd be [censored] out of luck in no time flat.
Also, is it CONFIRMED (i know its rumored to be such) that poisons will last more then 1 swing? If they dont... That will kill the DPS factor of them because you'd have to re apply them. ALSO, dont forget that you'd run out super quickly, unless you spent way too much time hoarding them before hand...