Like was already said your Qual point difference with the other team is two either way, but if you Co-Op and win you have the have a four point qual score increase which will help you against ALL the other high ranked teams.
Plus if you DO lose the match, because upsets never happen right

, you can still get the two qual points, which is a whole lot better than zero.
Seems pretty straight forward to me, Co-Op is important everytime.