Since they won't have at-home versions of the films to watch, potential Oscar voters are supposed to see these movies in theatres, like regular folk. But, of course, this won't work out in reality. Some of the Oscar voters are too busy, too far flung, maybe too frail, to go to a theatre that's showing a contender film ... certainly they cannot go to ALL the movies. And a great many independent, foreign, or financially unsuccessful films cannot arrange to have theatrical showings for the Oscar voters; so they'll be completely neglected.
Working in the business, I have received several of the screeners seeking my vote in various awards shows and the quaility of the tapes/DVDs is not deluxe at all, just a "quickly made copy viewable with the words like "For Academy Screening use only" scrolling across the top/and or bottom of the screen throught the film or every few minutes.
Yes, they are sent out before retail versions are produced causing the piracy scare.
Funny, most of my co-workers, including top notch directors have bootleg copies of many of theirs and others' films for their own viewing. Of course most would not go to the trouble of pirating them.