Because its faster. Matches would turn a 10 minute process into a halfhour or longer.

As mentioned above, if the queue doesn't pop in under 60~ seconds, withdraw and move some players around and try again. Both parties queue just French languange

Cumulative alone isn't all there is to consider, maybe median and range had something to do with it

I've had an attempt before where we were trying to fit a rank 8 and 12 players in and it just wouldn't work, they were too low compared to the others.