99% of the time, drafted players are better than undrafted. if you want to use an undrafted player for heavy minutes, it comes at the risk of that player not being of the caliber necessary in this league.
the outcome for which the rule was created - which is that owners can gain an advantage by focusing on commonly drafted players, because they're pretty certain the player they need won't get drafted - is not only not guaranteed to happen, because the player you need could always get drafted in a league with smart owners, but is also unlikely to happen even without the rule. how many players would you play for more than 1,700 minutes that didn't get drafted? i can't name them, but i also can't think of that many i would even want.
the one guy i want isn't that good. so, i think it's just an opportunity based on the draft system. we all hope certain bench guys won't get drafted. it shouldn't really matter how many minutes they play. if they're good enough, they'll get drafted, and if they're not, either they'll get drafted in the 6th, or they'll come with some sort of risk. it doesn't give any team an unfair advantage.