Benefit to covering pasta while cooking?
I see a benefit to covering the pot while bringing the water to a boil, as you will reduce evaporative cooling and get to temperature quicker.  I might also allow, that in some cases (maybe frozen pasta or too much pasta to water), when you add the pasta (thus cooling the water) replacing the lid will help return it to the boil quicker.  However, boiling pasta with a lid simply invites a boil-over situation.  Once boiling, covering is not influencing the cooking of the pasta.  Just leave it off.