For one thing, you'd most likely have a lot of sets of 10-6 or 10-8, and the "set score" might be 11-7. If you win the "set score" 11-7, score 10 points in the sets you win, and average, say 6 in the ones you lose, that's 152 points. In a normal game. If the final "set score" is 11-10, and each set is won 10-9, the final score of the match will be 200-199.

That brings up the other question of how satisfying it will be if the two teams end up tied based on total points.

Then you'd have to deal with teams not knowing how much time to plan for in a normal game. For players who genuinely need to be on a minutes restriction, that won't help.