I know they make you run faster while blinding you, but why do they make your attacks more accurate?

Well, if you use a weapon that has speed as the governing attribute, like short blade skill, then it would work better due to the higher speed rating.

Not necessarily. The "governing attribute" merely shows what attribute's "multiplier" is affected whenever the skill increases. The attribute may have no effect on the actual use of the skill, which I believe is the case with weapons.

It's a bug with the blind magic effect, instead of making you less accurate it actually makes you more accurate. The http://www.tesnexus.com/downloads/file.php?id=19510 fixes this, and many other things.

I had a feeling it had something to do with the blind effect, but I thought it was because I was using resist magic and it was giving me the opposite effect. I dont think this is a glitch i want fixed though